Cross posted over at GT.
First things first:
1: Any attempt to duplicate / simulate, actual or otherwise, is at own risk.
2: I firmly believe this device is in compliance with ATF "can own it, can build it" guidelines.
3: I have no illusion that results will be definitive.
4: Laugh with me, I have no metal working knowledge or tools :)
Now the "Why?"
I got into 10mm a couple of years ago, and being a reloader...
Have all the usual published sources, and initially stayed there. Started playing with QL, and discovered McNett's data.
Very carefully ventured off book, worked up loads with powders there was no data for, measuring everything measurable along the way. 44 powders, 9 primers, 79 different bullets, and 811 loads later, everything is intact. The G20 looks and works as new, and the worst offence is a slightly smiled case (AF barrel, 20# spring, 200 XPT @ 1,275).
That said, from early on I've wanted to know psi.
I've read enough, it's not as simple as a universal chamber from HS, and a piezo from PCB (capital setup. Regardless of equipment, nobody knows what the actual pressures are).
PT II, the only economical, "don't need an engineering degree" option available.
Challenge is, a strain gauge requires a round chamber. Try finding that in 10mm.
The Contender is an option, but $. You can buy an AERO barrel...
Chose a LW barrel (my FIL owns a mill and lathe, and graciously showed me how to turn the chamber to round).
18 months of conceptualizing, a year since I purchased the PT II, and this is what I came up with:
Through the many mental incarnations, I ended up with a metal base, mounted to heavy drawer guides, bolted to a second wood base that would be "field mounted' to a table.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_1.jpg)
I certainly could have continued used my FIL's lathe and mill, but the 5 hour round trip simply didn't work. To secure the barrel I used an inexpensive barrel vice. Machine work would be rudimentary: An old Harbor Freight hobby drill press; Cordless drill; A few taps; A square.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_2.jpg)
The aluminum stock was as purchased from a local hardware store's 'scrap' pile, absolutely overpaid for it.
The metal plate glides on heavy duty drawer guides that are bolted to the wood platform. The springs handle recoil. No idea if it'd work, a complete guess.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_3.jpg)
Mocked up.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_4.jpg)
Drilling / tapping the thrust block / breech face.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_5.jpg)
Doing my best to transfer thrust block holes to the metal base.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_6.jpg)
Thrust block / breech face drilled & tapped. Pictured is the 1st version of the firing pin assembly. The spring creates tension as the pin (threaded rod) is drawn back, the two nuts against the block control the pin's strike depth.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_7.jpg)
Barrel in vise, chambered dummy round against breech face.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_8.jpg)
Barrel loose in vise, drawn away from breech face, exposing firing pin. The firing pin (or striker) is a threaded rod, turned down (for the section that passes through the thrust block) by mounting in the drill press and wrapping with sandpaper.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_9.jpg)
To chamber a round, the vise must be loosened and the barrel drawn towards the front. Insert a round, slide the barrel up to the breech face, tighten the vise.
Not wanting any adventure, I needed a "safety".
The nut pictured pulls the firing pin (striker) out of contact from the primer. The round can be chambered, the vise secured, and the firing pin drawn back to "loaded" all with no danger of a primer strike.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_11.jpg)
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_12.jpg)
To be "compliant", the device needed a "grip". Searching the garage I found inspiration :)
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_13.jpg)
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_14.jpg)
2nd version of the fire control.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_15.jpg)
Initial testing (proof of concept) was done at distance with a pull string (Was't going to risk a $30 strain gauge without knowing if it worked!). "Use" trigger will be as simple as a length of fishing line routed from the release through a hole in the wood platform to the grip. The "trigger" will consist of a large key ring tied to the fishing line - Grip the "grip", finger in the key ring, pull!
I'm considering a momentary switch on the grip, triggering a solenoid to release the pin. Neat, but a complication that's not necessary.
Before firing while holding the grip, a safety shield will be mounted to the rear of the wood platform.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_16.jpg)
In action, tested yesterday, 2/11.
http://10mm-reloaded.com/Pressure_Trace_II_platform/platform.mp4 (http://10mm-reloaded.com/Pressure_Trace_II_platform/platform.mp4)
Today I'll attach the strain gauge and finalize a methodology for calibration.
Not likely I'll secure proof loads, I'll have to use a wide range of book loads, comparing a good size sample of reported pressures with my own results.
Again, I have no illusion that my results will be gospel, but carefully calibrated I believe the numbers will be useful.
And the setup should easily be converted to other calibers.
At very least this project has sparked my imagination a bit, and drained my wallet of $1,250 :)
Potential #'s as early as next weekend.
Very cool 8), I commend you and your efforts! Carry on! ;D
Thanks Shawdow!
If the weather cooperates I'll be calibrating next weekend!
All gussied up :)
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_19.jpg)
The other half of the operation.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/PTII_platform_17.jpg)
Count me in as another one who is following this with great interest.
Really cool.
Amazing what you can build with a drill and ingenuity.
(Cross posted over at GT)
Finally decent enough weather to try this contraption out :)
It was a quick trip, and everything functioned as expected.
Since I don't have proof loads, I put together five published recipes with the hope of getting in the ballpark of published #s.
Example:
Published: 155 XTP; Win brass; 6.5gr Universal; 1.260; WLP; 5"; 22.6K
Mine: 155 XTP; Starline; 6.5gr Universal; 1.260; WLP; 4.6"
Challenge - There's enough variables in comparing handloads to published without differing components, yet, for now, those additional variables exist.
Ten shots with the above load proved very consistent results, albeit low at an average of 16.3K.
Underwood's 200gr JHP's trace was chopped (flat top), and only produced 19.4K (Per Recreational Software, chopped traces could mean barrel swelling).
155 XTP / 8.9gr Autocomp (published 35.7K) tested at 24K.
Given that 4 of my 6 working brain cells fell asleep about an hour ago, thought process is / things to consider:
1: Per Recreational Software (RS): All things being equal, results will often be well below published numbers (due to publisher using worst case scenario (tightest chamber, etc).
2: Barrel is brand new (3 shots fired prior to today), and likely could benefit from a few boxes of hot rounds to settle in dimensions (see chopped trace reference above).
3: Dimensions entered into the software are critical, chamber ID being a challenge without the proper tool, which I don't own (used my digital calipers). I've ordered a casting kit, will have the proper measurement by next outing.
4: Too tired to figure out what #4 is...
I'm pleased with the initial results, but frustrated at the same time. Didn't help that I couldn't read the laptop screen (left the easy-up at home), the Sheriff wasn't too pleased my Discovery Pass (use-the-forest-tax) wan't with me, and 10 other people stopped to use the spot I was at.
I'm confident that, with a couple more outings, I can get things dialed in. Only question I can't answer right now (driving me nuts, just the way I'm wired) is: Once everything is working to the best of my ability, and I'm still getting lower than published #s, do I accept RS's explanation (Industry publishers using "worst case scenario"), or do I "correct" the software to show what's published?
Guess the only way to know is to send one of my loads, and my chamber, to a professional lab. = lol $.
Thoughts?
?
That is what I have tried to understand with that system all along...you need to adjust the input to get results of output.
This system is based on the stretch of the strain gauge that is wrapped around the barrel surface.
This might can help you do a comparison to dial in the data...
(https://i.postimg.cc/Dzqjdr70/Alliant-Datapg44-zpsffcd250d.jpg)
Good luck getting things sorted out.
All I can say is WOW !
Thanks Shawdow.
Next steps:
Run 50 rounds of nuclear through it, settle in the chamber.
Cast for absolute chamber measurement (curious to compare cast to my inside caliper measurement).
Reset the strain gauge.
Continue to test published loads (Hodgdon lists components used).
If, after the above, results are significantly lower than published numbers I'll enter a correction within the software.
Interested to see if a high pressure load reads near published after correction for a low pressure round.
At least I'm having fun :)
NICE WORK! Seems I'm late to the party. :( Better late than never. 8) This is exciting stuff! I've been lusting after one of those Pressure Trace units for many years now. Just never been able to swing the funding which is probably more attributed to poor money management than anything else. ::)
Is the LW barrel 4.6 inches long like a standard Glock 20 barrel?
Quote from: Benchrst on February 25 2017 09:37:27 PM MST...or do I "correct" the software to show what's published?
Thoughts?
My thought would be yes to that. Though I'll be curious to find out, if after you've corrected for one published load, if any other published load agrees with that correction factor. Wouldn't surprise me if one powder manufacturer's published data doesn't agree with another's. But who knows. Testing should tell within reason. I suspect you will still have to resort to an educated guess, just a much closer one than if you didn't have any published data to compare with.
I'll be anxiously watching for all future developements as you move forward. Keep up the great work! And BTW, nice job on that shooting contraption you built.
Quote from: The_Shadow on February 25 2017 10:03:51 PM MSTThat is what I have tried to understand with that system all along...you need to adjust the input to get results of output.
Does that leave room for negative issues?
Thanks Redline!
Next step is to season the chamber a bit (if the weather EVER breaks), attach a new strain gauge, and resume testing.
I understand the necessity, or rather the needed ability, to make a universal correction for a specific gauge setup - THAT particular gauge, it's unique install, the glue used...
And I agree with your thinking, and it's my intent to make a correction (should it be necessary) and compare against multiple published loads. If the correction puts my results near reported then success. At least in reporting a specific load by published standards.
My components are a close to published as can be, but even if I, Alliant, Sierra, and Hornady tested identical loads, on the same day, at the same altitude, with the same cosmic alignment, we'd get different results.
Quote from: Benchrst on March 13 2017 08:00:12 PM MDT...but even if I, Alliant, Sierra, and Hornady tested identical loads, on the same day, at the same altitude, with the same cosmic alignment, we'd get different results.
I would expect that if you all were using a different system to test pressure. But I tend to think if you all used a properly set up PTII, calibrated properly (even if not to an identical ammo load), that you would all get relatively close results. The main variances being altitude and different lots of powder. The PTII is already figuring in barrel temperature. Just my thought.
Quote from: REDLINE on March 14 2017 06:26:37 AM MDT
Quote from: Benchrst on March 13 2017 08:00:12 PM MDT...but even if I, Alliant, Sierra, and Hornady tested identical loads, on the same day, at the same altitude, with the same cosmic alignment, we'd get different results.
I would expect that if you all were using a different system to test pressure. But I tend to think if you all used a properly set up PTII, calibrated properly (even if not to an identical ammo load), that you would all get relatively close results. The main variances being altitude and different lots of powder. The PTII is already figuring in barrel temperature. Just my thought.
I agree, but chamber dimensions have to be a factor.
My test 'chamber' is a LW barrel turned down to round. I suspect it's on the tighter side, but I really don't know.
Regardless, the weather is supposed to clear for two days in late August ;D
Quote from: Benchrst on March 14 2017 08:05:17 PM MDTI agree, but chamber dimensions have to be a factor.
My test 'chamber' is a LW barrel turned down to round. I suspect it's on the tighter side, but I really don't know.
Makes sense. Neat that the PTII takes that into account too.
QuoteRegardless, the weather is supposed to clear for two days in late August ;D
LOL
Might be worth a chamber casting to see how close to SAAMI minimum it is.
Quote from: sqlbullet on March 15 2017 08:01:11 AM MDT
Might be worth a chamber casting to see how close to SAAMI minimum it is.
Funny you should mention that! I have a # of cerrosafe, and have cast the chamber.
Guess I should head over to the SAAMI site :)
I too must be late to the party, I missed this one. Great job, please keep on posting about it. Really fascinating.
Removed the strain gauge, "seasoned" the barrel with a few spicy loads, and attached a new gauge. Tested today, regardless of the load all traces flat-top at 20K psi. Sent everything over to RSI, have a suspicion that it has to do with my barrel chamber walls, specifically how thin they are.
If that's what comes back from RSI I have a plan B :)
I have wondered if an actual piezoelectric pressure sensor could be mounted. There was a video of a Beretta 92 which was modified to accommodate the sensor and still cycle the gun. They had welded bushing to the barrel to hold the sensor.
From Jim at RSI
"The problem is that a 10mm barrel is so thin it exceeds the normal
design parameters of the system. It is designed so with a normal
bolt action rifle and 1.25" O.D./.308 dia chamber, anything that
exceeds safe pressures will flat line. There is a workaround.
The above spread sheet provides instructions for manipulating the data
so things fall into a normal range. The numbers are already entered
for your barrel so start with step 3.
Once microstrains have been captured and saved to file they cannot be
changed but after you alter the dimensions to fool the system into
having enough range for the thin barrel, the system will no longer flat
line. Microstrain values will no longer be valid."
A public thanks to Jim at RSI for getting back to me so quickly!
I'm going to try Jim's suggesting, perhaps as early as this weekend. If it works, fantastic. Otherwise I'll get an ASR pistol barrel or buy a .40 blank and have it reamed.
I believe the end result of this project will be success :)
Progress today :)
Jim at RSI has been very helpful, and after entering in correcting #s that would allow the system to 'cope' with my thin-walled barrel I tested two loads.
155 XTP 9.8gr 800X trace:
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/05.10.17_Lone_Wolf_155_XTP_9.8_800X_WLP.jpg)
200 XTP 7.8gr 800X trace:
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/05.10.17_Lone_Wolf_200_XTP_7.8_800X_Rem_2.5.jpg)
Hodgdon's results for these two loads:
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/Hodgdon_155_and_200_XPT_pressures.jpg)
I have no expectation that my #s will match Hodgdon's, but a consistent "close" over a wide variety of loads would help to validate the system.
The trace is still flat topping, and I've reached out to Jim to get his continued input.
The cut-down LW barrel may or may not have to be abandoned - regardless, two additional barrels will be used, each one to validate the other's readings.
I ordered a Kaw Valley AR barrel, it's chamber's walls are significant in comparison to the LW. I should have it in about a week.
Green Mountain's run of .40 blanks will be complete by the end of the month, so with delivery and reaming it's likely 60 days out.
I feel good about this system eventually providing useful and accurate information :)
Glad you have seen some results and getting to work with the system despite the shortcomings...
This is awesome. If there werent a wedding I was on the hook to fund in a few months I would be duplicating your system.
After you have it calibrated, I would love to see some graphs from some of the Buffalo Bore and Underwood offerings.
Quote from: sqlbullet on May 11 2017 08:29:07 AM MDT
This is awesome. If there werent a wedding I was on the hook to fund in a few months I would be duplicating your system.
After you have it calibrated, I would love to see some graphs from some of the Buffalo Bore and Underwood offerings.
Trust me, I'm quite curious :)
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/Pressure_Trace_II_10mm_factory_ammo_to_test.jpg)
Quote from: Benchrst on May 10 2017 09:47:16 PM MDT
Progress today :)
I tested two loads.
155 XTP 9.8gr 800X trace:
200 XTP 7.8gr 800X trace:
Looking good. Did you get velocities too?
QuoteI ordered a Kaw Valley AR barrel, it's chamber's walls are significant in comparison to the LW. I should have it in about a week.
Green Mountain's run of .40 blanks will be complete by the end of the month, so with delivery and reaming it's likely 60 days out.
I feel good about this system eventually providing useful and accurate information :)
What will be the lengths of the two new barrels?
Quote from: REDLINE on May 13 2017 01:59:11 AM MDT
Looking good. Did you get velocities too?
I didn't. As soon as the system is delivering consistent results I'll add a chrono to the mix.
QuoteI ordered a Kaw Valley AR barrel, it's chamber's walls are significant in comparison to the LW. I should have it in about a week.
Green Mountain's run of .40 blanks will be complete by the end of the month, so with delivery and reaming it's likely 60 days out.
I feel good about this system eventually providing useful and accurate information :)
What will be the lengths of the two new barrels?
The Kaw is 4.5", the Green Mountain will likely end up a 6" and a 10", since it ships as a 22" blank.
Quote from: Benchrst on May 13 2017 09:06:57 AM MDTThe Kaw is 4.5", the Green Mountain will likely end up a 6" and a 10", since it ships as a 22" blank.
These 3 barrels will all have a strain gage mounted and be used for pressure testing? That's what I was thinking you were getting at when you mentioned them earlier but I am wondering if it is possible to mount a strain gage to the Kaw barrel if it is this one; https://www.kawvalleyprecision.com/Kaw-Valley-Precision-4-5-10MM-4150-QPQ-AR-15-Barr-p/kvp-10mm-bbl-4.htm (https://www.kawvalleyprecision.com/Kaw-Valley-Precision-4-5-10MM-4150-QPQ-AR-15-Barr-p/kvp-10mm-bbl-4.htm)
I couldn't find the Green Mountain barrel you mentioned.
I found their website, assuming this is it; http://www.gmriflebarrel.com/ (http://www.gmriflebarrel.com/)
Can you provide a link to the specific barrel blank they offer that you're interested in?
Hello Redline, I think what Benchrst was saying was that the barrels need to be a certain diameter for the strain gauges to calibrate correctly when installed.
QuoteFrom Jim at RSI
"The problem is that a 10mm barrel is so thin it exceeds the normal
design parameters of the system. It is designed so with a normal
bolt action rifle and 1.25" O.D./.308 dia chamber, anything that
exceeds safe pressures will flat line.
The one he made is not large diameter enough and the strain gauge is flexed as wrapped around the smaller diameter.
Looking at the Kaw barrel it is likely the purpose for this project...
And, from green mountain I bet he is just getting a blank.
http://www.gmriflebarrel.com/bx3840-25-round-barrel-blanks-40-caliber-winchester/
Quote from: REDLINE on May 15 2017 02:53:47 AM MDT
Quote from: Benchrst on May 13 2017 09:06:57 AM MDTThe Kaw is 4.5", the Green Mountain will likely end up a 6" and a 10", since it ships as a 22" blank.
These 3 barrels will all have a strain gage mounted and be used for pressure testing? That's what I was thinking you were getting at when you mentioned them earlier but I am wondering if it is possible to mount a strain gage to the Kaw barrel if it is this one; https://www.kawvalleyprecision.com/Kaw-Valley-Precision-4-5-10MM-4150-QPQ-AR-15-Barr-p/kvp-10mm-bbl-4.htm (https://www.kawvalleyprecision.com/Kaw-Valley-Precision-4-5-10MM-4150-QPQ-AR-15-Barr-p/kvp-10mm-bbl-4.htm)
I couldn't find the Green Mountain barrel you mentioned.
I found their website, assuming this is it; http://www.gmriflebarrel.com/ (http://www.gmriflebarrel.com/)
Can you provide a link to the specific barrel blank they offer that you're interested in?
Redline
Yes, that's the Kaw Valley barrel I purchased. I should receive it today, and if I'm lucky get it on the lathe Wednesday :)
The Green Mountain .40 blank can be seen here: http://www.gmriflebarrel.com/40-blank-40-cal-10mm-raw-round-barrel-blank-1-x-20/ (http://www.gmriflebarrel.com/40-blank-40-cal-10mm-raw-round-barrel-blank-1-x-20/) (Sql was close :) )
The issue with my current barrel is the thin chamber walls - it's rate of expansion when fired is exceeding the systems data capture design. A 'number fix' from RSI improved the results but still resulted in cropped traces at upper pressures. Jim @ RSI stated that I could incrementally increase the 'number fix' until the issued is resolved, which I intend to try.
If I can get my current barrel to trace w/o crops I'll keep it in the mix, comparing it's results to that of the Kaw Valley and Green Mountain with future testing.
While each barrel's chamber is unique, and will provide unique results, the idea is to get similar results with three unique barrels - a validation if you will.
So much time, so much $, so close :)
Quote from: The_Shadow on May 15 2017 07:05:44 AM MDT
Hello Redline, I think what Benchrst was saying was that the barrels need to be a certain diameter for the strain gauges to calibrate correctly when installed.
The one he made is not large diameter enough and the strain gauge is flexed as wrapped around the smaller diameter.
Looking at the Kaw barrel it is likely the purpose for this project...
RSI didn't suggest the issue was how 'tightly wrapped' the gauge was, though that certainly may be a contributing factor.
Exactly, I purchased the Kaw Valley barrel because of it's generous chamber walls (a least in comparison to the 'turned round' Lone Wolf).
Finding an off-the-shelf solution has been a challenge, as most .40 barrels are configured for autos. I initially contacted Lothar, they were less than helpful, and the cost...
Also considered was TNW's ASR pistol barrel, but their website states you'll need a tax stamp to purchase (due to it being a drop in for the ASR). Didn't really want to hassle my way through that on the phone.
Good thing I'm persistent, otherwise I'd have an expensive dust collector :)
:)
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/Pressure_Trace_II_platform_10mm_Lone_Wolf_vs_Kaw_Valley_1.jpg)
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/Pressure_Trace_II_platform_10mm_Lone_Wolf_vs_Kaw_Valley_2.jpg)
That looks much better for pressure testing!
That's a lot of steel around that chamber.
Quote from: Ridgerunner665 on May 15 2017 05:02:43 PM MDT
That looks much better for pressure testing!
That's a lot of steel around that chamber.
Yes, .997 OD vs .623 OD :)
I'll profile forward of the chamber Wednesday and glue up a strain gauge, hopefully I'm testing this weekend :)
I'm watching this closely... Very interested in seeing some numbers.
Benchrst, wishing you all the best in this endeavor! Good luck!
Quote from: Benchrst on May 15 2017 10:55:48 AM MDTIf I can get my current barrel to trace w/o crops I'll keep it in the mix, comparing it's results to that of the Kaw Valley and Green Mountain with future testing.
While each barrel's chamber is unique, and will provide unique results, the idea is to get similar results with three unique barrels - a validation if you will.
Interesting, thanks for explaining! Can't wait to see the results unfold.
Earlier when you referred to Green Mountain
reaming the barrel blank(s), is that
reaming for the purpose of cutting a 10mm Auto chamber(s)?
Yes. Chamber ream.
Quote from: REDLINE on May 16 2017 05:50:34 AM MDT
Earlier when you referred to Green Mountain reaming the barrel blank(s), is that reaming for the purpose of cutting a 10mm Auto chamber(s)?
Yes, as SQL said, cutting the chamber.
The GM barrel is a "blank", it's rifled .40 but isn't cartridge specific (has no chamber).
Since it's a bull profile I can cut it into whatever lengths I need and ream (chamber) each section. Likely a 4", 6", and 10".
Definitely adds up to a nice selection of barrels to compare with and against. As your project unfolds and develops I find myself more and more intrigued in anticipation of the well rounded and extenuating results it will ultimately produce!
Thanks for the encouragement guys!
The goal is to have a consistent, repeatable test platform up and running by July, and there's light at the end of the tunnel :)
Today's progress:
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/Pressure_Trace_II_10mm_platform_Kaw_Valley_barrel_profiling_2.jpg)
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/Pressure_Trace_II_10mm_platform_Kaw_Valley_barrel_profiling_4.jpg)
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/Pressure_Trace_II_10mm_platform_Kaw_Valley_barrel_profile_complete_1.jpg)
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/Pressure_Trace_II_10mm_platform_Kaw_Valley_barrel_installed_1.jpg)
Looking great... 8)
Quote from: Benchrst on May 17 2017 05:09:05 PM MDT(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/Pressure_Trace_II_10mm_platform_Kaw_Valley_barrel_profile_complete_1.jpg)
Very Nice
On the chamber end of the barrel, is the milled section basically the full length of the chamber? And will the strain gage be mounted in the center (lengthwise down barrel) of that milled section?
Quote from: REDLINE on May 18 2017 04:51:05 AM MDT
Very Nice
On the chamber end of the barrel, is the milled section basically the full length of the chamber? And will the strain gage be mounted in the center (lengthwise down barrel) of that milled section?
Yes, and no :)
The strain gauge needs to be mounted perpendicular to the bore axis.
Installed:
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/Pressure_Trace_II_platform_10mm_Kaw_Valley_strain_gauge_installed_1.jpg)
Case chambered, dummy round set for reference in relation to strain gauge placement (gauge needs to be about center of cartridge, and 1/4" from differing metal thickness).
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/Pressure_Trace_II_platform_10mm_Kaw_Valley_strain_gauge_installed_2.jpg)
The bits of black around the gauge connectors and substrate are what my rubber glove left behind after the glue setup, last time it was bits of skin :)
Looking great! Hoping your endeavors will pay the dividends you are working so hard to achieve! :D
Quote from: The_Shadow on May 18 2017 11:57:11 AM MDT
Looking great! Hoping your endeavors will pay the dividends you are working so hard to achieve! :D
I should probably check in, see if I'm still married :)
Quote from: Benchrst on May 18 2017 11:07:50 AM MDTYes, and no :)
The strain gauge needs to be mounted perpendicular to the bore axis.
Case chambered, dummy round set for reference in relation to strain gauge placement (gauge needs to be about center of cartridge, and 1/4" from differing metal thickness).
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/Pressure_Trace_II_platform_10mm_Kaw_Valley_strain_gauge_installed_2.jpg)
The pictures are worth 1000 words! BTW, nice job with the pics!
Is there a notion either way, if you change the parameters of the PTII to respond properly to the original thinner barrel, that it will throw things back off when setting up for the new thicker steel barrel(s)?
Quote from: REDLINE on May 19 2017 06:34:06 AM MDT
The pictures are worth 1000 words! BTW, nice job with the pics!
Is there a notion either way, if you change the parameters of the PTII to respond properly to the original thinner barrel, that it will throw things back off when setting up for the new thicker steel barrel(s)?
Thanks!
No, each barrel has it's own profile that's loaded prior to testing.
Good to know.
Green Mountain .40 cal blank was in stock today so that's been ordered, should be about 3 weeks before it's chambered and ready to test.
Initial testing with the Kaw Valley barrel may happen this Friday, and would consist of matched published loads, factory loads, and misc loads.
The list can be seen here (link contains undocumented data, use at own risk!): http://10mm-reloaded.com/Pressure_Trace_II_platform/results/10mm_Pressure_Trace_II_pressure_test_results.html (http://10mm-reloaded.com/Pressure_Trace_II_platform/results/10mm_Pressure_Trace_II_pressure_test_results.html)
If there's any specific interests I can try to work them in, the 'bullet library' of what I have available: http://10mm-reloaded.com/load_data/supplemental/40_cal_bullet_details.html (http://10mm-reloaded.com/load_data/supplemental/40_cal_bullet_details.html)
Can't Wait!
Did some limited testing on the 24th and ran into a few functionality issues: The striker spring was binding when compressed, slowing the striker on release. This caused the need for multiple restrikes; The barrel clamp profile isn't the same as the barrel, which allows a bit of left-or-right swing when it's cinched down - this created off-center primer strikes.
Solutions :)
Scribed line indicating the center of the striker allows for simple cartridge alignment.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/10mm_Pressure_Trace_II_platform_striker_centerline.jpg)
Looking over the thrust block, centering the cartridge.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/10mm_Pressure_Trace_II_platform_striker_centerline_2.jpg)
The striker release "keepers", kept in place by one bolt each, were rotating inward under the spring pressure, in turn binding release. Not having bolts short enough (impact the track on the underside) I drilled small holes in the base (where the "2nd" bolt would go) and filled with epoxy. Worked :)
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/10mm_Pressure_Trace_II_platform_striker_release.jpg)
Striker spring mod, epoxy and a washer.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/10mm_Pressure_Trace_II_platform_striker_spring.jpg)
Washer prevents the thin wire spring from bingding against the all-thread striker.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/10mm_Pressure_Trace_II_platform_striker_spring_mod.jpg)
Fun part! He who sets his striker 'depth' too deep will blow primers!
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/10mm_Pressure_Trace_II_platform_blown_primer_2.jpg)
Blew the striker completely out of the thrust block, bent one of the 'keepers', and trashed the striker keeper-pin link. Luckily I travel with really cheap pliers, back up and running in minutes ;)
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/10mm_Pressure_Trace_II_platform_blown_primer_1.jpg)
Results? I'm working on those ;)
I won't have the Green Mountain barrel chambered and ready to test for almost a month, and until I have two similar results I hesitate to post specifics.
So...
Loads use new brass from same order, CCI 300 primers from same tray (seated with hand primer), powder measured on a Gem Pro 250 to within 0.02 of intended. Brass sized on Lee die, flared to minimum required on Lee universal, seated on lee within two thousandths of intended. Crimp as specified.
Generic load "1": New Jagemann brass, Redding taper (noise at end of trace will be explained later).
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/generic/generic_1_Jagemann.jpg)
Generic load "1": New Starline, Redding taper.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/generic/generic_1_Starline_Redding_taper.jpg)
Generic load "1": New Starline, FCD taper.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/generic/generic_1_Starline_FCD.jpg)
Generic load "2": New Jagemann, Redding taper.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/generic/generic_2__Jagemann.jpg)
Generic load "2": New Starline, Redding taper.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/generic/generic_2__Starline_new.jpg)
Generic load "2": Used Starline (case may be 1X or 8X), Redding taper.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/generic/generic_2__Starline_MX.jpg)
At 2 or 3 traces each the results are hardly definitive, but the exercise was an attempt to create a result that matched RSI's suggestion regarding my inquiry into low pressure readings.
I've considered that including multiple chambers to the testing will only complicate results, even it they're similar, but it will be part of the process.
I'm beginning to think this is a multi-year process, and will involve independent labs.
Good thing I'm persistent, and don't care about retirement funds :)
And, apparently, I have nothing better to do on a Friday night at 7:55.
Pretty lame!
:)
Well, at least you are getting some data. What was the powder and charge weight?
Quote from: The_Shadow on May 26 2017 09:03:38 PM MDT
Well, at least you are getting some data. What was the powder and charge weight?
A published load that stated 35K.
Other than lot numbers, my components are identical, save the case - don't have access to new Remington or Winchester.
RSI suggested that case hardness (we know Starline is soft) can have a significant impact on results, hence using a variable (Jagemann).
My chamber is not the labs, and my conditions are not theirs, but a 7 or 8K difference?
Bramwell and Oehler proved the strain gauge accurate, but without a second chamber I won't publish results. Either my setup is in error, or the manu's are padding the crap out of their numbers (I'm not suggesting this).
Ultimately, a ballistics testing lab will be contracted.
This will take months, if not years :)
Quote from: Benchrst on May 26 2017 08:27:58 PM MDTResults? I'm working on those ;)
I'm thrilled seeing any continued progress no matter how long it takes and thank you for sharing! 8)
Quote from: Benchrst on May 26 2017 08:53:15 PM MDTI've considered that including multiple chambers to the testing will only complicate results, even it they're similar, but it will be part of the process.
Maybe, but regardless I still think there's a chance of benefit in the case there may be some noteworthy information to gain from testing with different barrel lengths. And then again maybe not. I do feel it is worth looking into at least.
Quote from: Benchrst on May 26 2017 09:34:35 PM MDTEither my setup is in error, or the manu's are padding the crap out of their numbers (I'm not suggesting this).
I can think of reasons for and against the manufacturers padding their numbers and who knows what else.
The question I have is;
Do the manufacturers numbers agree with each other's? To test that numbers would be needed from more than one manu of the same load which are probably few and far between.
Maybe one bullet manu and one powder manu, not affiliated with each other in any way, tested the same load that they both listed a pressure for? And then they probably still wouldn't agree with the possibility of different test barrel chambers and overall conditions?
I guess it probably will take an unbiased ballistics testing lab to iron out a correction factor to set up you equipment to, and make your different barrels agree with each other.
However it comes together, keep up the AWESOME WORK!
It is likely a calibration that is going to be need to yield the results from this type of system using a strain gauge. The RSI Trace system is providing some data with pressures being what they are.
1884 Diff between Hi-Lo
982 Diff between Hi-Lo This was the best for test for Generic load #1
2210 Diff between Hi-Lo
The total diff generic Load #1 was 2514 over all three test
935 Diff between Hi-Lo
128 Diff between Hi-Lo This was the best for test for Generic load #2
2343 Diff between Hi-Lo
The total diff generic Load #2 was 3885 over all three test
Glad to see the RSI system producing samples with tight numbers for some of the testing. With some fine tuning you are likely to see better results and data.
Thanks for sharing your work in progress...
QuoteSAAMI recognizes two pressure-measuring systems. The preferred system is the piezoelectric transducer system with the transducer flush-mounted in the chamber of the test barrel. Pressure developed by the burning propellant exerts force on the transducer through the cartridge case wall causing the transducer to deflect, creating a measurable electric charge. Pressures measured with this system are expressed in units of "pounds per square inch" (abbreviated psi).
The second, older system employs a copper crusher cylinder which is compressed by a piston fitted to a piston hole into the chamber of the test barrel. Pressure generated by the burning propellant acts on the base of the piston forcing the piston to move, thereby permanently compressing the copper cylinder. Pressures measured by this system are expressed in "Copper Units of Pressure" (abbreviated as "CUP").
Random thoughts and hypotheticals, in no particular order...
A 35K 'recipie' tests at 30K in my rig, 32K at lab A, and 34.5K in lab B. What does that tell us?
What is the possible pressure swing between differing chambers using identical cartridges? Is 8K even possible?
With slow burning rifle powders we know that jamming can have a significant effect on pressure, does that apply to fast burning powders?
I'll load a batch, splitting it into 'standard oal' and 'touching the lands' and post the results.
It would be simple enough to test the hottest boutique ammo, set a global PSI correction within the trace software raising the reading to max, and call it a day. All subsequent testing would 'corrected'. But, is it reality for THAT chamber?
Know that: The PT II records an 'event', and plots a trace according to the parameters entered into the program. Any 'event' can be opened with the software and traced with new parameters (PSI correction, barrel dimensions, brass dimensions), producing a new result. IE, there's always the option of entering a correction later.
The Green Mountain barrel offers opportunity: 1 blank cut into multiple lengths, cut with the same reamer (heck, could even ream both ends of the same section). The ability to test two barrels
that are 'identical' would validate strain gauges / installation. I've considered what would be gained by having two strain gauges installed over the same chamber.
Blowing a primer = about 2K reduction in reading :)
Cyanoacrylate adhesives have a shelf life. The first two gauge installations (LW barrel) used glue supplied by RSI. The Kaw Valley installation used approved Loctite 401. I've read that anything less than a perfect bond will yield lower-than-reality pressures. How fresh was the Loctite?
More glue from RSI has been ordered.
So, I'll continue, organize the data best I can, and we can figure out what it all means :)
I think a key to arriving at the most accurate results between various comparisons will be starting with as consistent a load as possible. That begs the question; What load recipe to use geared toward really tight consistency? I would think the same type of load would be best to use as a verification load over time too.
Quote from: REDLINE on May 28 2017 07:58:06 AM MDT
I think a key to arriving at the most accurate results between various comparisons will be starting with as consistent a load as possible. That begs the question; What load recipe to use geared toward really tight consistency? I would think the same type of load would be best to use as a verification load over time too.
Just some random thoughts on this...
Powders too fast or too slow might make this a bit fussy.... If it were me, I'd use Power Pistol, as it is the most consistent and lenient pistol powder I've used across a wide range of bullet weights.
Bullet weight.... I'd go middle of the road there too...180 grains.
A match primer...I prefer CCI.
Full on match prepped brass.... Sorted for weight, measured for capacity, flash hole centered and checked, trimmed to length so the crimp will be repeatable, etc.
Remove every variable that is within reach.
And to answer a related question that was asked earlier.
Is an 8,000 psi swing from the same chamber/load possible? I'd say yes, I believe the variation in some brands of brass could do that.
For the sake of discussion.... Call it 13.5 grains of usable case capacity (from Nosler 200 grain load data)... That is 13.5 grains of water.
10% of 13.5 is 1.35, and 1.35 grains of water is a VERY small amount.... The point is, it doesn't take much to create a significant difference in case capacity that will swing pressure back and forth by several thousand psi.
I'm gonna run some QuickLoad projections to illustrate this.... I'll post them in a few minutes...I need to measure the chamber of the new barrel anyway.
Yeah.... Just messing around with QuickLoad and changing the case capacity by 1.3 grains I'm getting 5,000 psi pressure swings.
Checking my Starline brass....I get capacity differences as much as 2 grains from within the same lot of brass.
So, there is an easy several thousand psi variable...
QuickLoad isn't an exact science, especially with straight wall rounds... But it can do some useful calculations.
Thanks for contributing Ridgerunner!
I have QuickLOAD as well, might prove useful in all of this.
This project is a bit like the show Lost, every time a question is asked it's answered by three more questions :)
To reduce the possibility of a strain gauge / attachment issue:
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/10mm_Pressure_Trace_II_platform_Kaw_Valley_barrel_second_strain_gauge_installed.jpg)
Apparently I do have Winchester brass :)
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/Pressure_Trace_II_10mm_platform_Winchester_brass.jpg)
Fred Meyer? I might have forgotten. You live in the PNW?
Quote from: Pablo on May 28 2017 10:25:24 PM MDT
Fred Meyer? I might have forgotten. You live in the PNW?
I do, the ammo was included with a Parker purchase.
Reminds me, gunsmith still has that POS, it's been years (probably an ATF 'abandon').
Oh well :)
Was able to do a few tests today.
Note: Some loads may be above book max, use at own risk!
155 MG 12.8gr #7 CCI 300 1X Norma brass Kaw Barrel strain gauge (SG) #2
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/053117_75_degress/155_mg_12.8_aa7_cci300_1x_norma_brass_Kaw_SG_2.jpg)
155 MG 12.8 #7 CCI 300 1X Winchester brass Kaw SG #2
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/053117_75_degress/155_mg_12.8_aa7_cci300_1x_winchester_brass_Kaw_SG_2.jpg)
200 XTP 7.8 800X CCI 300 new Starline Kaw SG #2
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/053117_75_degress/200_xtp_7.8_800x_cci300_new_starline_Kaw_SG_2.jpg)
Buffalo Bore 21B Kaw SG #2
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/053117_75_degress/BB_21B_Kaw_SG_2.jpg)
Underwood 200 JHP (item 247) Kaw SG #2
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/053117_75_degress/UW_200_jhp_item_247_Kaw_SG_2.jpg)
Underwood 200 JHP (item 247) Kaw SG #1
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/053117_75_degress/UW_200_jhp_item_247_Kaw_SG_1.jpg)
Wow. Really cool.
I may have missed it, but how do those traces stack against computer simulation load programs? (I can't think of the name of the popular one)
Very interesting numbers...Just thinking ( I know that is very dangerous here ) and manipulating some numbers.
When you compare the numbers especially the IMR800X 200 XTP 7.8 800X CCI 300 new Starline Kaw SG #2
High 24541 psi, Middle 22502 psi, Low 22323 psi
This load as listed by Hodgdon is shown as 1130 fps @ 32,500 psi
32500
-24500
8000 difference
BB 29,300 add 8000 = 37,300 (We both measured these as having 14.6 / 14.8 grains AA#9)
UW 28,600 add 8000 = 36,600
UW 31,200 add 8000 = 39,200
Taking in account the difference the BB and UW loads are inside the SAAMI MAP for the 10mm.
And that's what I'm (we're) working towards, an intelligently arrived at corrective PSI.
I'll get at least two chambers out of the Green Mountain barrel, so additional data points, or potentially additional confusion :)
I have three more strain gauges en route, and am considering alternative installation points:
1: Exactly as the others, centered over the case as it sits in the chamber.
2: Back a bit, just ahead of the web.
3: Just forward of the case mouth, entering a zero value for case thickness in the software.
To simplify this for myself, either the modulus is off for both my barrels, or my chamber pressures are as reported. The GM barrel may, or may not, offer clarification.
:)
Quote from: Pablo on May 31 2017 06:28:00 PM MDT
Wow. Really cool.
I may have missed it, but how do those traces stack against computer simulation load programs? (I can't think of the name of the popular one)
Pablo
QuickLOAD predicts this:
(http://10mm-reloaded.com/random/images/Pablo_QL_prediction.jpg)
Pressure Trace II is reporting this:
(http://10mm-reloaded.com/Pressure_Trace_II_platform/results/053117_75_degress/155_mg_12.8_aa7_cci300_1x_norma_brass_Kaw_SG_2.jpg)
Both results, at this point, should be taken with a grain of salt ;)
Shadow did the same thing I immediately did...check pressures on the 800X load and derive a crude correction value to apply to the other loads. Great minds? :))
benchrst, I agree they are to be taken with a grain of salt, but OTOH, your results have an appropriate curve and are consistent with each other. This indicates your test rig is stable and repeatable. Which means all that is needed is corrective values and you have a real winner there.
Additional chambers will be HUGE. I expect the result to vary some, but will help us laymen see the differences the chamber cut can make.
Once additional thought...The SAAMI pressure values are for a minimum chamber. Such chambers are carefully cut to minimum dimensions and pressures in minimum chambers will be higher for the same load as a production chamber.
These chambers are effectively production chambers. While it is possible that this one happened to be cut to minimum, it is more likely that it is over minimum and will therefore report a bit low on pressure compared to a SAAMI test chamber.
One of the most perfect Quick Loads screenshots that was given was for Power Pistol powder.
155 grain Gold Dot over 11.0 grains of Power Pistol making 1463 fps that shows 37,616 psi
(https://i.postimg.cc/fTyNThVN/155-GD-w-11-gr-PP.png)
Maybe Benchrst could do a comparison to get a benchmark testing this load with his pressure rig.
Then these two others were getting close to the magic 37,500 psi mark...
8.0 grains under a 200 XTP @ 1178 fps was shown at 36,881 psi
9.9 grains under a 180 Precision Delta FMJ @ 1289 fps at 36,236 psi
Included in the Pressure Trace manual:
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/10mm_pressure_trace_platform_calibration.jpg)
I had read this before but forgotten about it. It does seem to support what's being reported in my chambers vs. published data.
The new GM barrel offers lots of possibilities (multiple chambers), and one thought is to cut a chamber with a standard reamer, and another with a custom PTG made to SAAMI min.
It seems there is a fudge factor and finding that number will allow more precise info...
Article detailing some of the SAAMI testing;
http://archives.sensorsmag.com/articles/0599/0599_p93/main.shtml (http://archives.sensorsmag.com/articles/0599/0599_p93/main.shtml)
Another publication with very detailed pressure testing equipment and setups for Ballistic Lab. (interesting reading)
http://www.pcb.com/Linked_Documents/Aerospace/AD-BallisticPressureGuide_LowRes.pdf?utm_source=Cal+Nation+%23106+%28August+2016%29+-+FINAL&utm_campaign=Cal+Nation+%23106+August+16&utm_medium=archive (http://www.pcb.com/Linked_Documents/Aerospace/AD-BallisticPressureGuide_LowRes.pdf?utm_source=Cal+Nation+%23106+%28August+2016%29+-+FINAL&utm_campaign=Cal+Nation+%23106+August+16&utm_medium=archive)
I wish we could get our hands on the pressure test rig that Mike built and used for the SwampFox 10mm testing to add to the data.
Thanks for the links!
I had looked over PCB's site when I first got this hair brained idea, but decided selling my children to fund such a project probably wouldn't have worked out (average kids, don't think I would've got much for em').
A bit interesting (PCB pdf) is the statement that conformal sensors are located slightly behind the heel of the bullet.
My gauge placement puts it splitting the heel, at least with a 200gr XTP.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/10mm_pressure_trace_platform_strain_gauge_placement.jpg)
Curious if moving the gauge back would have any effect.
Quote from: The_Shadow on May 31 2017 07:19:20 PM MDT
Very interesting numbers...Just thinking ( I know that is very dangerous here ) and manipulating some numbers.
When you compare the numbers especially the IMR800X 200 XTP 7.8 800X CCI 300 new Starline Kaw SG #2
High 24541 psi, Middle 22502 psi, Low 22323 psi
This load as listed by Hodgdon is shown as 1130 fps @ 32,500 psi
32500
-24500
8000 difference
BB 29,300 add 8000 = 37,300 (We both measured these as having 14.6 / 14.8 grains AA#9)
UW 28,600 add 8000 = 36,600
UW 31,200 add 8000 = 39,200
Taking in account the difference the BB and UW loads are inside the SAAMI MAP for the 10mm.
My thoughts exactly.
Quote from: Benchrst on June 01 2017 04:20:38 PM MDTCurious if moving the gauge back would have any effect.
Even if it would I don't see what would be gained. Just my general thought and should be taken with a grain of salt!
Quote from: The_Shadow on May 31 2017 07:19:20 PM MDT
Taking in account the difference the BB and UW loads are inside the SAAMI MAP for the 10mm.
Maybe. Possibly even probably.
My thinking:
These test are only of two-three rounds and are very preliminary. A proper test would include a sample of 10 rounds, and would have no round exceed 40,500 psi corrected, or 32,500 based on the current correction factor. And would have a MAP of 37,500. The second Underwood 200 grain has only two data points, with a 3,486 PSI deviation. If the low value is an outlier, and the average is closer to the high value, then the MAP (corrected) will be over 37.5K and chances are at least one round will exceed the 40.5K.
Of course, if the high value is the outlier, then this is just ammo loaded right to the max.
Quote from: sqlbullet on June 02 2017 08:26:48 AM MDT
These test are only of two-three rounds and are very preliminary.
Exactly.
First challenge was to get functionality, that's been done. Second, show repeatability, getting there.
Still think this factors into what we're seeing.
(http://10mm-reloaded.com/Pressure_Trace_II_platform/images/10mm_pressure_trace_platform_calibration.jpg)
Random thought: Should cut the Green Mountain barrel long enough to attach a MagnetoSpeed :)
That would be interesting to see velocities and how they match up. However you could weld a stub to the barrel to do the same thing allowing attach of MagnetoSpeed, if you need a shorter barrel.
Not a bad idea... That would eliminate another variable.
Well what has Benchrst been doing? Have a look at the progress and documentations he's done! 8)
http://10mm-reloaded.com/index.html (http://10mm-reloaded.com/index.html)
Quote from: The_Shadow on September 08 2019 06:57:10 PM MDT
Well what has Benchrst been doing? Have a look at the progress and documentations he's done! 8)
http://10mm-reloaded.com/index.html (http://10mm-reloaded.com/index.html)
Thanks for posting a "heads-up", lots of GREAT info thanks to Benchrst!
My own blog said that I didn't die and that I'd be back to it soon, that was back in Feb of 18' :))
A few promotions later and I've found myself spending the bulk of my weekends motionless (lazy) :)
I did buy a barrel blank from Green Mountain in the "correct" composition (4150 maybe, not certain) (according to Recreational Software), so I'm hoping that future testing is more inline with factory reported pressures.
Maybe next spring :)
(http://10mm-reloaded.com/dumping_ground/third_pressure_trace_barrel.jpg)
Glad to see you back here and updating your status and sharing the project! 8)
Quote from: Benchrst on September 10 2019 08:52:14 PM MDTMaybe next spring :)
Looking forward to it! I'ld be most curious to see what PSI it shows for various UW factory loads.