We are all here because we enjoy the 10mm. It pushes the ballistic boundaries of standard size auto-loading handgun.
In pursuit of these boundaries many forum members hand load their own ammunition. Others reload for economy, providing generally more shots per dollar than factory ammunition.
Now for the warning.
You will often find loads in this forum which exceed published load data. I, like others have been known to exceed published data on occasion. In such situations I personally have carefully and meticulously measured to the best of my ability how my gun is behaving with a given load and observer closely for any signs on each and every cartridge that I have entered a dangerous realm.
There can be many reasons why published data stops at a given point, and those reasons are usually not disclosed in published data. Also, each gun is an entity unto itself and may react differently. Industry accepted margins of error are built into published data as well to account for possible extremes in environmental conditions.
The stance of the forum is to follow published load data. Exceeding such data may result in serious injury. Maximum loads should be in new brass of quality manufacture, using load data of the same vintage as the powder. In the absence of published starting loads, maximum loads should be reduced by 10%. The loader should work up, usually in 5 steps, checking for signs of danger or excess pressure until the maximum is reached. If pressure signs become evident before the maximum is reached, you have reached the maximum for your gun. Fall back to the last safe load and record it as a maximum in your data.
Since most of use do not possess equipment to carefully measure pressure other means must be used. One of the best methods is to measure case head expansion. Visually inspecting primers is NOT a reliable indicator of excess pressure. Case head expansion is unique to each gun and should be tracked when working up max loads. Any sudden change in case head measurement should be treated as an indicator of excessive pressure, and the next lower charge should be considered maximum for your gun.
Unless otherwise indicated as safe, maximum loads should not be reduced by more than 20%. Under certain conditions, especially in large magnum rifle calibers, such excessively reduced loads can produce dangerous pressure spikes. In handguns, the largest danger of very light loads is a bullet stuck in the barrel undetected.
You may choose to exceed published load data, stopping only when indicated by your good sense or in some cases loss of digits, eyesight and/or massive blood loss (I saw a similar statement in the most recent Handloader and couldn't help but plagiarize it). We hope no forum members are ever injured while shooting, whether from factory ammo or hand loads.
We suggest every forum member acquire and maintain for reference a library of load data from a variety of sources and reference that data carefully anytime working up a load. We further suggest any load you see in this forum, or any other internet forum, be carefully cross referenced against published load data before being attempted in your gun. Even if the load falls within the range of published data, follow that standard guidelines to work up to the charge.
We would ask that members as often as possible indicate loads that are over published maximums, and also indicate the source of load data they are using or used as a starting point.
Further, we ask that not only the charge, but the other components, especially primer brand and type be carefully documented. Changing from one primer brand to another of the same type can create pressure variations of as much as 10,000 psi or more according to recent data developed by Handloader.
As always, we appreciate your contributions to our community and look forward to many your many tales regaling the great 10mm Auto cartridge!
--Mitch
Quote from: sqlbullet on July 06 2012 12:19:09 PM MDT
Case head expansion is unique to each gun and should be tracked when working up max loads. Any sudden change in case head measurement should be treated as an indicator of excessive pressure, and the next lower charge should be considered maximum for your gun.
--Mitch
For me a G20 is the platform (bone stock for now).
What do you use for a baseline measurement when you start out not knowing what pressure any given factory loaded round is at in the first place? I suppose a book load of listed pressure value would be a good place to start for a baseline case head measurement?
Redline's question is the same as mine. Even with very light loads, my stock G20 barrel produces case head expansion that is on the upper limits of what people consider "stopping" points.
Quote from: Turo on July 06 2012 09:08:39 PM MDT
Redline's question is the same as mine. Even with very light loads, my stock G20 barrel produces case head expansion that is on the upper limits of what people consider "stopping" points.
That's mainly what makes me wonder. Though my experience in case head measurement is limited. It exists, but again is limited.
Original post is deleted. It has become clear to me that people have misunderstood, or misinterpreted my intention of this post, so I'm pulling it down. I've noticed this post referenced and/or copied in other sights and forums since I posted it, and a lot of it has been used and/or interpreted in ways that I did not intend. I still stand behind the information that I originally shared, however.
Thanks Taterhead, for a well reasoned and thorough answer based on what would seem to be extensive experience. Much appreciated.
Sorry for the delay in response. This weekend largely had me away from technology.
My response would duplicate taterheads in about every way. Buffalo Bore and Underwood both start with new starline brass, which provides a convenient factory baseline on max loads. Measuring as you work up and looking for smiles or sudden/erratic case head readings.
If you're going to use case expansion for reading pressure, here's the method I suggest. Buy a large lot of factory ammo. Wait 6 mo. to a year to see if there are any recalls on that lot of ammo for pressure or other issues. Test a statistically significant sample of it in the test gun. Pull the bullets and primers from the remainder of the lot and use it for your own load development, again using a statistically significant sample size. This way you have a reference to a known safe standard. Make sense?
Quote from: Hubcap on August 11 2012 08:37:51 PM MDT
If you're going to use case expansion for reading pressure, here's the method I suggest. Buy a large lot of factory ammo. Wait 6 mo. to a year to see if there are any recalls on that lot of ammo for pressure or other issues. Test a statistically significant sample of it in the test gun. Pull the bullets and primers from the remainder of the lot and use it for your own load development, again using a statistically significant sample size. This way you have a reference to a known safe standard. Make sense?
But one still wouldn't know what safe standard they were at, right? How would you know if it was ammo loaded to 30,000psi or 35,000psi, or whatever? I guess I'm not understanding how that basis leads to a standard in case head measurement, except for the factory load itself that was used for the testing to begin with. What am I misunderstanding?
Quote from: Taterhead on July 07 2012 07:14:28 PM MDT
Great writeup sqlbullet!
In my G20, I have found that measuring maximum case expansion around the pressure band has yielded VERY useful information about relative pressure. By pressure band, I am referring to the circumference of the case that is a little more than 1/8" above the extraction groove. Having done several dozen unique load workups for my G20, and I have found consistent measurements that track from one workup to the next.
I have found that maximum case expansion (Using STARLINE brass) consistently measures:
Starting charges: 0.431 - 0.432"
Medium-warm: 0.433"
Book maxes: 0.433 - 0.434"
A bit beyond book maxes: 0.434"
Max acceptable expansion in my G20: 0.434"
Expansion beyond 0.434" begins to reveal Glock smiles (frowns)
Buffalo Bore and Underwood both produce ammo within SAAMI specs, but toward the upper end. They also conveniently use Starline brass. I almost exclusively use Starline brass, and it is pretty popular with 10mm handloaders. Great stuff.
Buffalo Bore loads consistently have a max case expansion of a hair hunder 0.434". That coincides with my observed upper limit in my G20.
When I do load workups, I carefully observe brass condition, and measure the expansion around the pressure band. As I approach 0.434", I know that I am getting to the maximums in my gun. I also know if I continue to push, I will get to Glock smiles, and I will have gone too far.
Examples of loads that expand to 0.434", or close to it, in my G20 chamber:
135 Nosler JHP @ 1700 fps
155 XTP @ 1425 fps
180 gr BB factory load @ 1335 fps
200 gr XTP @ 1200
Brass from my range ammo expands to about .0433". That would be a 180 @ 1175 fps.
An important consideration: different makes of brass will yield different expansion characteristics. Nickel is especially noticeable. That is one reason that I stick to Starline brass (it is also good quality and the best price). Also, that is why I do 100% of load workups in new brass. I do not use reloaded brass because work-hardened brass will expand differently than new brass.
Buffalo Bore or Underwood Ammo is a great place to start to establish an upper limit mark for those using G20 chambers. Each chamber is slightly unique, so my observations might not track with another G20 chamber. But for those reloading for a G20 barrel, most will likely find 0.434" will track consistently with max loads and/or Buffalo Bore and Underwood factory rounds. Pushing beyond that creates smiles, and loads producing smiles should be backed down.
I typically load 10 rounds per increment and increase by 0.2 or 0.3 grain increments depending upon the type of powder and how close to max. All are hand weighed and verified with check weights. At the range, I do the following routine:
Shoot one round. Holster.
Observe chrony reading.
Retrieve case.
Inspect overall condition (looking for smiles, brass flow, gas leakage at the primer pocket, primer condition, unburned powder, powder residue on case indicating poor chamber seal, etc. etc.)
Carefully measure the max expansion around the pressure band.
Chrony data, brass condition, and case expansion should track with expectations. If not, then I do not keep shooting the next charge increments. I have pulled plenty of bullets over the years.
If all is good-to-go, then rinse and repeat. For the next string, I use a different target location so that I can examine groups. This is a time-consuming process, but has enabled me to safely develop some nice ammunition.
Hi Everyone! I recognize some of you from over @ GT.
Taterhead,
This is great info! I am also just starting reloading for my new G20. You give some very specific practical tips on loading for this incredible handgun. Yet the tips are good for ANY loading for any high-power round and platform. It seems being methodical and disciplined is the key if you chose to push envelope levels of loads such as max+ 10mm. Do you know of or have any worthy publications or software programs that help model internal ballistics?
Thanks much and I'll be seein' y'all 'round town. ;)
- Dave
Quote from: Hubcap on August 11 2012 08:37:51 PM MDT
If you're going to use case expansion for reading pressure, here's the method I suggest. Buy a large lot of factory ammo. Wait 6 mo. to a year to see if there are any recalls on that lot of ammo for pressure or other issues. Test a statistically significant sample of it in the test gun. Pull the bullets and primers from the remainder of the lot and use it for your own load development, again using a statistically significant sample size. This way you have a reference to a known safe standard. Make sense?
How would you know what powder or primers they are using?
Sorry if that wasn't clear.
Use the brass, not the powder/primers. The idea being you have the same pressure vessel and it should react similarly as you reach your pressure limits.
Underwood and Buffalo Bore make this simple since they use Starline brass. Easy enough to just buy your own brass from starline.
Quote from: REDLINE on August 12 2012 06:52:02 PM MDT
Quote from: Hubcap on August 11 2012 08:37:51 PM MDT
If you're going to use case expansion for reading pressure, here's the method I suggest. Buy a large lot of factory ammo. Wait 6 mo. to a year to see if there are any recalls on that lot of ammo for pressure or other issues. Test a statistically significant sample of it in the test gun. Pull the bullets and primers from the remainder of the lot and use it for your own load development, again using a statistically significant sample size. This way you have a reference to a known safe standard. Make sense?
But one still wouldn't know what safe standard they were at, right? How would you know if it was ammo loaded to 30,000psi or 35,000psi, or whatever? I guess I'm not understanding how that basis leads to a standard in case head measurement, except for the factory load itself that was used for the testing to begin with. What am I misunderstanding?
You are right that you will not know the actual pressure number. Choose Buffalo Bore or Underwood. They are both going to be closer to the
upper limit, but within SAAMI specs. They also use the same brass that many of us use - so apples-to-apples.
Hope that helps.
Quote from: Taterhead on August 28 2012 10:56:08 PM MDT
Quote from: REDLINE on August 12 2012 06:52:02 PM MDT
Quote from: Hubcap on August 11 2012 08:37:51 PM MDT
If you're going to use case expansion for reading pressure, here's the method I suggest. Buy a large lot of factory ammo. Wait 6 mo. to a year to see if there are any recalls on that lot of ammo for pressure or other issues. Test a statistically significant sample of it in the test gun. Pull the bullets and primers from the remainder of the lot and use it for your own load development, again using a statistically significant sample size. This way you have a reference to a known safe standard. Make sense?
But one still wouldn't know what safe standard they were at, right? How would you know if it was ammo loaded to 30,000psi or 35,000psi, or whatever? I guess I'm not understanding how that basis leads to a standard in case head measurement, except for the factory load itself that was used for the testing to begin with. What am I misunderstanding?
You are right that you will not know the actual pressure number. Choose Buffalo Bore or Underwood. They are both going to be closer to the upper limit, but within SAAMI specs. They also use the same brass that many of us use - so apples-to-apples.
Hope that helps.
Sorta agreed, but still not the same lot of brass, which might give false or misleading readings.
I am more into accuracy vs. speed. Since I have NEVER found the most accurate load to be around a max recipe, I don't go there. My usual 10mm reload is rather more on the low end. And they are effective.
(http://img.photobucket.com/albums/v196/Gandog56/dwgroup.jpg)
Quote from: Taterhead on July 07 2012 07:14:28 PM MDT
I have found that maximum case expansion (Using STARLINE brass) consistently measures:
Starting charges: 0.431 - 0.432"
Medium-warm: 0.433"
Book maxes: 0.433 - 0.434"
A bit beyond book maxes: 0.434"
Max acceptable expansion in my G20: 0.434"
Expansion beyond 0.434" begins to reveal Glock smiles (frowns)
Wow! Most of my brass, which shows a shoulder where the sizing die stopped (but measured just above the extraction groove and below the sized area) measures about 0.424", and the nastiest looking brass is measuring up around 0.427-428". This is also Starline brass, and loads just below max (generally these were 10.6-10.7 gr HS-6 under a 165 gr JHP).
These would have been fired in a G29 and an EAA Witness Hunter.
My Glock 29 produces the above numbers that Taterhead reported. My Witness and Para both are tighter chambers and have smaller expansions.
Further, I find that the occasional just beyond max load will smile brass in my Para when it doesn't in my Glock. The Para chamber was hogged out a bit by a previous owner right at the back. I think the combination of a tight chamber plus less than ideal case head support means that some loads generate more pressure in the para, hence the smile, even thought the case head support is similar to the glock.
Goes back to working up and testing loads in YOUR gun.
Quote from: Bongo Boy on June 02 2013 10:31:43 PM MDT
Quote from: Taterhead on July 07 2012 07:14:28 PM MDT
I have found that maximum case expansion (Using STARLINE brass) consistently measures:
Starting charges: 0.431 - 0.432"
Medium-warm: 0.433"
Book maxes: 0.433 - 0.434"
A bit beyond book maxes: 0.434"
Max acceptable expansion in my G20: 0.434"
Expansion beyond 0.434" begins to reveal Glock smiles (frowns)
Wow! Most of my brass, which shows a shoulder where the sizing die stopped (but measured just above the extraction groove and below the sized area) measures about 0.424", and the nastiest looking brass is measuring up around 0.427-428". This is also Starline brass, and loads just below max (generally these were 10.6-10.7 gr HS-6 under a 165 gr JHP).
These would have been fired in a G29 and an EAA Witness Hunter.
What is your post-size case mouth, wall, web and head diameters? Your sizing die may be defective (too small or too little chamfer at the opening). ANSI/SAAMI spec. is .4231" at the mouth and .4250 at the base/web.
My most accurate loads are max book and farther. But not in the worthless OEM Glock barrel! LOLOLOLOL I've never shot the worthless Glock barrel.
(http://www.cleanmpg.com/photos/data/638/medium/50y.jpg)
G20 is a Blue Dot load.
The .357 Mag is a honest 1425 fps chronograph load in that pistol. 1375 out of the wifes 60 Pro.
The 10mm BD and Mag ( fed ) primer load is a honest 1575 fps load.
Why play with the useless 135gn Nosler bullet?
Quote from: blastfact on December 07 2013 05:45:19 PM MST
Why play with the useless 135gn Nosler bullet?
What makes the 135gr Nosler bullet worthless?
I wish people would take a little more time to elaborate, rather than just throwing something out there! :-\
Here is my take on what he was trying to convey...
When driven at the higher speeds, it fragments to the point of shearing off pieces and separating from its core.
Nosler's 135's are also slightly under the 0.4000" as measured...many have been 0.3990" - 0.3995", that and the shorter bore riding section being shorter tend to make it less accurate at longer distance.
I think this is why not many bullet makers are making their's any lighter than the 155 grain offerings. ::)
I use them as I walk a lot in urban terrain. I shot them at 50 yrds and not so good.
Nobody should just go and use a max recipe right off. Work your way up to a max in small increments looking for any signs of overpressure (Flattened primers, primers blown out, extremely hard extraction)
I have never found the most accurate recipes near the very top velocities.
I agree with Gandog,,, ;D I intend to go for accuracy.... not speed,,, I rounded up some blue dot and a couple hundred rounds of brass and some 180 gr. hard cast bullets... and when the dies that I have coming , arrive here , then I will start working up some loads... probably 5 at a time, increasing a tenth of a grain with each bracket of 5....looking at 8.2 grains of powder.... but the local guy reccomends to start with 5.2 gr..... ideas???
DocModisett, i can tell you from personal experience with Blue Dot it needs to be pushed to burn cleanly and provide you some consistent velocities. With that said, I have worked with the cast 175gr TC's sized at 0.4015" for years and loads between 10.2 gr. and 10.4 gr. of the Blue Dot (velocity of 1160-1180 fps) were the most accurate from my S&W 1006. What do I mean by accurate? 130 yards skeet sized targets consistently, and even smaller.
Quote from: blastfact on December 07 2013 05:45:19 PM MST
My most accurate loads are max book and farther. But not in the worthless OEM Glock barrel! LOLOLOLOL I've never shot the worthless Glock barrel.
(http://www.cleanmpg.com/photos/data/638/medium/50y.jpg)
G20 is a Blue Dot load.
The .357 Mag is a honest 1425 fps chronograph load in that pistol. 1375 out of the wifes 60 Pro.
The 10mm BD and Mag ( fed ) primer load is a honest 1575 fps load.
Why play with the useless 135gn Nosler bullet?
So, what barrel are you shooting?
Doc,
Please let me know I'm reloading 180 FMJ, and using blue dot
In my Glock 20 180gr fmj I found 10gr. to be the most accurate load using Blue Dot.
Most accurate very often is just below max. Nearly full cases result in very uniform ignition and velocities.
Correct me if Im wrong,brass fired from glock pistols are not supposed to be reloaded! Yes or no?
That bubble, bulge after being fired is now a weak link, yes or no.
I recently read a new designed die to push the bulge back to straight before being resized. That is FACT.
Is that brass now 100% perfect to resize,reload fire? Lee
Smiled cases that are buldged badly should not be reloaded. Slight bulge or other brass from Glocks is fine to reload. There is a sticky with pictures.
Quote from: sliclee on March 17 2016 08:05:02 PM MDT
Correct me if Im wrong,brass fired from glock pistols are not supposed to be reloaded! Yes or no?
That bubble, bulge after being fired is now a weak link, yes or no.
I recently read a new designed die to push the bulge back to straight before being resized. That is FACT.
Is that brass now 100% perfect to resize,reload fire? Lee
Smiles are bad. Discard the brass. Period. Bulges (bubbles), on the other hand, iron them out with a Lee FCD bulge buster or Redding pass-through die. I've been reusing Glock-fired brass for 25 years. No problems.
Here is the video link of the Redding GRX setup being used. I also use the LEE FCD die with ts guts removed as a Bulge Buster setup....
Vid showed pic of smiles but he didn't talk much about the problem of a damaged case...
But still explained the problem well enough.
When I need, I use the Lee sizer without guts, but it's only every now and then. Usu the regular sizing die solves the problem for me.
But looking at the price of the GRX die at $82 (carbide), I think I'd just opt for a LW barrel at $99.
As I have mentioned before using the LEE FCD without the guts,I "pass - through" size all 10mm, 40S&W, 357Sig and 9x25 Dillon cases prior to regular sizing and depriming. The reason is a simple one for me, I achieve 100% reliability of feeding and functioning, therefore it becomes the essential part of my handloading practices.
I also have utilized the "pass - through" sizing process with 380 ACP and 45 ACP using the appropriate LEE FCD dies.
I am about the start "pass - through" for 9mm cases as soon as I can get the Lee Carbide Factory Crimp Die 9x18mm (9mm Makarov) to work with...
Pass through for 9mm is a problem. It is actually not a true straight wall pistol case, it has a slight taper. Pass through destroys that taper.
I have never seen a spec that indicated it had slight taper.
Justin
http://www.saami.org/pubresources/cc_drawings/Pistol/9mm%20Luger%20-%209mm%20Luger%20+P.pdf (http://www.saami.org/pubresources/cc_drawings/Pistol/9mm%20Luger%20-%209mm%20Luger%20+P.pdf)
9mm is a taper cartridge, and can be 'bulge busted' with a 9mm Mak FCD.
Quote from: Turo on July 06 2012 09:08:39 PM MDT
Redline's question is the same as mine. Even with very light loads, my stock G20 barrel produces case head expansion that is on the upper limits of what people consider "stopping" points.
Unfortunately case head expansion is not a valid indicator of total pressure. A larger than spec chamber - GLOCKS, will allow a brass case that flows like plastic under high pressure, to expand to meet the chamber wall, then "spring back" as brass does. This results in a "measured" greater than recommended case head expansion yet has in reality told you NOTHING about total pressure. The case can ONLY expand to the limit of the chamber. Different alloys of brass will result in different "rebound" or contraction amounts of the brass...so total case head expansion tells you nothing. A fully flattened primer tells you a LOT more....as does a "smeared" primer that indicates the slide started unlocking even before the spring-loaded firing pin could get out of the way....except in a Glock or XD which has a spring HOLDING the firing pin forward as the slide cycles!
I gotta dissent here.
Case head expansion is not a reliable indicator between guns. e.g. you can't measure a case head from your gun and compare it to a generic chart and know anything.
But, for a given firearm, case heads will expand consistently as pressure increases (too a point). I have seen this in all my guns. And I maintain data for my guns for just this purpose.
That said, there are some very specific rules that have to be followed for this method to work.
1. You have to use a micrometer that measures to ten-thousandths. .001" is not good enough.
2. You have to do all your tests with new brass from the same maker, ideally from the same lot. Used brass will have work hardened to varying degrees and this will affect the outcome.
3. It is useful to have some reference data. Underwood loads at the very edge of SAAMI spec, and uses virgin starline brass. I consider them a valuable reference for case head expansion on max loads.
I would also comment that 10mm is a high enough impulse round that it is not uncommon to get some firing pin wipe in many guns with perfectly safe loads. My Witness guns, for instance, wipe every primer, every time. This is because the slide acceleration overcomes the firing pin spring.
Quote from: Benchrst on July 05 2016 02:38:14 PM MDT
http://www.saami.org/pubresources/cc_drawings/Pistol/9mm%20Luger%20-%209mm%20Luger%20+P.pdf (http://www.saami.org/pubresources/cc_drawings/Pistol/9mm%20Luger%20-%209mm%20Luger%20+P.pdf)
9mm is a taper cartridge, and can be 'bulge busted' with a 9mm Mak FCD.
Now THAT I never thought of. But sounds good. I have way over 1000 cases laying around that I just may try that with.
Quote from: Benchrst on July 05 2016 02:38:14 PM MDT
http://www.saami.org/pubresources/cc_drawings/Pistol/9mm%20Luger%20-%209mm%20Luger%20+P.pdf (http://www.saami.org/pubresources/cc_drawings/Pistol/9mm%20Luger%20-%209mm%20Luger%20+P.pdf)
9mm is a taper cartridge, and can be 'bulge busted' with a 9mm Mak FCD.
The 9mm Luger is, in fact, a tapered cartridge. However, if you feel the need to "bulge bust" them, something is very wrong. Bulged 9mm brass is junk brass, and should not be reused. The 9mm case is robust, more so than the pressure it should ever be subject to (+P+). The brass is thicker in all dimensions (mouth, wall, web, and head), and volume smaller, than cases designed for significantly greater volume and higher pressure. If your 9mm brass is bulging, something is very wrong.
It goes back to not all brass is created equal either! The pressures for 9mm is all over the place Std pressure and +P and
+P+ as to are the chambers being anywhere from great support to loose as a goose...
Quote from: The_Shadow on July 22 2016 08:20:53 AM MDT
It goes back to not all brass is created equal either! The pressures for 9mm is all over the place Std pressure and +P and
+P+ as to are the chambers being anywhere from great support to loose as a goose...
No doubt. Since the 9mm was/is the preferred and most prolific SMG cartridge (by a WIDE margin) for nearly a century, the current design is also that old. It remains essentially unchanged, dimensionally. Modern metallurgy and manufacturing processes further improve the durability. With a maximum +P+ pressure similar to the .40SW (35K PSI), it should be a moot issue. They easily withstand the exceptionally "loose" and fluted chambers common in hyper-cyclic rate SMG's with no issues. Flute embossing common with .40SW and .45ACP is rarely seen on 9mm cases. Bulged brass is either depleted (used up, by whatever means), or severely over-pressured. Either way, not suitable for reuse.
I have seen and read where there has been some issues in the 9mm reloadings and yes the use of the 9mm Mak FCD die does help with bringing the lowest part of the cases back down to size. Especially guys who are shooting competition and are looking for the best reliability of feeding without stoppages.
Why are they not getting sized? The use of a carbide sizer die has a radiused opening and the thickness of the top of shell holder occupy the space. The older steel dies used less radius so they actually reached down a little more toward the extractor ring cut.
The pressures for +P and +P+ do add to some extra expansion in combination of loose chambers and yes those with excessive feed ramp bevels.
Here is some pressure info that is 9mm specific;
Quote9mm Plus Pressure Plus by Charles E. Petty
Basicly..... Is it worth it to beat the snot out of your firearm for a little extra?
The current SAAMI (Sporting Arms and Ammunition Manufacturing Institute) standard for 9mm Luger ammunition specifies a maximum product average chamber pressure of 37,400 p.s.i., but, the +P+ loads exceed this by a substantial margin. A limit of 42,000 p.s.i. has been proposed for this ammunition. For comparison, proof load pressure (nominal average) is set at 49,800 p.s.i. Now the situation is even further confused, for Remington has begun to market +P 9mm Luger ammunition with a proposed pressure limit of 38,500 p.s.i. To clarify, +P ammunition is available for commercial sale while +P+ loads are not.
All of this raises the question of what the civilian shooter can use in his gun. Even though the ammunition manufacturers take pains to insure that special law enforcement loads do not circulate in civilian channels, it is unrealistic to expect that some will not "leak" out. The same is certainly true for M882 service ammunition, and it is important that the civilian shooter who encounters any of these loads be able to recognize them and understand that this ammunition is different. M882 NATO ammunition as loaded by Olin Corp. (Winchester) and formerly loaded by Federal is currently specified to drive a 124 grain FMJ bullet at 375 meters per second (1230 f.p.s.), which puts it in nearly the same league as the various +P+ loads.
Winchester requires purchasers of +P+ ammunition to sign a release which states in part: "The 9mm 115 grain +P+ cartridges covered in this purchase order are specially loaded to achieve higher velocity. Therefore, the pressure level is higher than standard 9mm Luger cartridges. Individual cartridges may achieve pressure which may approach or exceed the proof load pressure a particular pistol may have been subjected to in factory proofing.
This cartridge is not recommended for use in any aluminum frame and/or cylinder pistols and may cause damage to modern steel pistols because of the higher pressures.
"THESE CARTRIDGES SHOULD BE USED IN MODERN PISTOLS ONLY. CHECK THE CONDITION OF THE PISTOL OFTEN. IF DOUBT EXISTS AS TO THE USE OF THESE CARTRIDGES IN YOUR PISTOL, CONSULT THE PISTOL MANUFACTURER." The demand for +P+ loadings has caused some consternation among firearm and ammunition manufacturers and there has been some finger pointing both ways. So, in an effort to clarify the situation, all of the major manufacturers and importers of the popular "wondernines" were queried about their position on the use of NATO and +P+ ammunition in their products. This is something of a hot potato as far as the firearms manufacturers are concerned, and most were understandably cautious or did not reply at all.
A Smith & Wesson spokesman indicated that S&W was not in favor of using +P+ ammunition, although it was studying the subject. This presents an interesting paradox, for the Illinois State Police, one of the first agencies to ask for +P+ loadings, is a major user of S&W
While increasing bullet velocity increases energy, it is questionable whether this is really meaningful in practical terms. A 200 f.p.s. increase in velocity (about what you get going from standard to +P+ 9mm ammunition) does not guarantee significantly better results in actual shooting situations. When you consider that this gain, roughly 15%, is accomplished at an increase in pressure that could be as much as 33%, it makes me wonder if it is all worthwhile.
Quote from: REDLINE on July 06 2012 08:39:23 PM MDT
Quote from: sqlbullet on July 06 2012 12:19:09 PM MDT
Case head expansion is unique to each gun and should be tracked when working up max loads. Any sudden change in case head measurement should be treated as an indicator of excessive pressure, and the next lower charge should be considered maximum for your gun.
--Mitch
For me a G20 is the platform (bone stock for now).
What do you use for a baseline measurement when you start out not knowing what pressure any given factory loaded round is at in the first place? I suppose a book load of listed pressure value would be a good place to start for a baseline case head measurement?
I fire a couple of factory loads that perform how I like. I measure the case bulge and record that and other relevant data. This is my baseline for my gun. I have used this method safely in .40 for many years.
Sent from my SHIELD Tablet K1 using Tapatalk
I'll be interested to measure case head expansion of rounds fired through the KKM barrel, noted for a tight chamber.
If I recall those using the KKM had 0.4280" chambers, you can measure the chamber to see. The area at the feed ramp will be larger and this is where you will see over expansion and SMILES develop on the casings if the pressures are too high...
Factory Glock barrels are usually 0.4340" inside the chamber, anything more measured on a fired case is over expansion.
If you slide comes out of battery too soon you could see expansion larger than the chamber size as the casing is being pulled out of the chamber and increasing unsupported areas...
Shadow, thanks for the comments. As I recall, I may want to play with a stronger recoil spring weight to retard the barrel from coming out of battery "too soon."
Hello everyone, I will do an intro later but stumbled on this thread while looking for decent load data for my 10mm. I ma most likely the outlier here as I generally shoot 10mm from a 14" barreled Contender that seems to like 180-200 grain bullets at book max where they typically suggest strongly not to use these loads in semi autos. I cannot speak as to why my specific Contender prefers these loads in the name of accuracy, but I'm betting that having all that extra barrel to use every bit of powder and build the velocity has a great deal to do with it. One additional note, you are now making me want to pick up a decent 10mm semi auto for perhaps primary carry duty, and move my 45 to back up. Nice thread, even if I'm a bit late to the party, glad I found the forum.
Casey
Welcome aboard Casey!
I completely agree with your assessment that you need a semi-auto 10mm for primary EDC. :D
Casey, welcome to the forum! I have some TC (only) 10mm data that someone shared with me...
Most of the data shown is equal to what I have seen in other manuals over the years with the exception being 2400 being shown about 1 grain higher. Although the standard 10mm Auto data for 2400 was shown at 36,000 psi.
The velocity due to the 14" Barrel length is up there over the standard 5" barrel data.
Thompson Center Contender ONLY Data
(https://s20.postimg.cc/xmxm4d4p9/10mm-tc-data.jpg)
Best regards! :D
Well, goodie! That manual uses my Blue Dot powder I use for my 10mm reloads.
Quote from: BillinOregon on April 08 2018 07:30:42 AM MDT
I'll be interested to measure case head expansion of rounds fired through the KKM barrel, noted for a tight chamber.
My G20 cases come out at .432-.433 for most of my loads
While my Sig 220/10mm cases are in the .426-.427 range for same loads.
It comes down to the chamber size, and all of the after-market barrels are much tighter then the stock Glock
Quote from: tommac919 on July 26 2018 09:14:29 AM MDT
It comes down to the chamber size, and all of the after-market barrels are much tighter then the stock Glock
Do the aftermarket barrels shoot as reliably as the stock barrel? I've always guessed that the well-known glock reliability stems at least partially from their loose chamber fit.
I have no issue with the glock stock barrel ( don't own an after-market )... For me with both my reloads ( Xtreme heavy plated 180s & Blue Dot ) and factory Win Stips / Sig V crowns there is better accuracy than I can do... tested both in a sighting rest and at 50ft have very small 5 shot groups of aprox <2"
Only issue is the brass being worked hard due to chamber
Quote from: Mike_Fontenot on July 26 2018 11:28:59 AM MDT
Quote from: tommac919 on July 26 2018 09:14:29 AM MDT
It comes down to the chamber size, and all of the after-market barrels are much tighter then the stock Glock
Do the aftermarket barrels shoot as reliably as the stock barrel? I've always guessed that the well-known glock reliability stems at least partially from their loose chamber fit.
Yes some of the aftermarket barrels can shoot tighter groups than the factory Glock barrels. especially with lead alloy bullets.
The Factory Glock barrel with the looser chamber tends to be more forgiving with respect to the feeding, especially with reloaded ammo where small discrepancies to correct resized and properly crimped cartridges that may not pass a cartridge case gauge. The tighter chambers of the aftermarket barrels will show that the cartridge out of spec will show this quickly...
Because of bulging (AKA Glock Bulge but it also happens in other firearms as well) very low on the cartridge case just above the extractor cut, is why I started pass through sizing all of my 10mm and 40S&W brass. By performing the pass through all of my finished rounds will pass the cartridge case gauge and feed reliably in all of my barrel chambers... :D