Discussion with Hodgdon about 800-X

[Taterhead]

I was on the phone with Hodgdon today going over a couple of powder questions about one of the "lesser" service cartridges. The tech was in a talking mood so I drifted the conversation over to 800-X and 10mm Auto data. I asked about the reason why they hold the maxes to relatively low pressures. There has been a good deal of speculation about why, and I thought I'd pick his brain a bit.

Some have speculated that it is because it meters so poorly, but he said that wasn't the reason. They electronically dispense powders in their testing lab, and metering is not a consideration. Plus many other powders don't meter well either, and they aren't similarly de-rated.

To paraphrase, he said that when they see things that they don't like in pressure testing at higher pressures, they hold down the maxes accordingly. And that would hold true for the 800-X/10mm data. Plain and simple. Seemed like a pretty straightforward explanation to me.

Then he went into speculation mode to hypothesize about why it might not track predictably at higher pressures. Since it is lofty, it gets to complete case fill. Some powders behave differently when nearing complete case fill or at slight compression. Again, the latter part was his own speculation about why the testing results were as they were.

One thing I like about the reloading industry is that I have found some of the vendors to have very friendly service: Hodgdon, RCBS, Starline, and others.

I thought I'd pass that along.

[cwlongshot]

So basically they say that the "think" it could be bad??  Apologies but that's simply a non answer. 

There are reasons for everything. Stopping because they THINK some thing bears the necessity to prove this out. I just don't believe they stopped because of a feeling.

Tell us pressure spikes as is seen with lil gun...FINE! But a feeling???   

CW

[The_Shadow]

When you look at the data from the years past for 800X, the charges were actually reduced fairly recently.  This was because people did have issues with pressure spikes that popped primer out and yes blew out cases where less supported,

Here is an example of the Original Data Label for 10mm


Here is some newer data from Hodgdon before their web page changed;


When you look over the data it doesn't even list the 135 grain bullet using 800X...

I can say that Underwood used it in his loads in the past and the 135 grain Nosler I tested had 11.8 grains of IMR800X that yielded 1702 fps but it blew the primer out of the StarLine brass, which kicked the casing out from under the extractor leaving the casing in the chamber so it wasn't ejected.  I have to think that it was a loose primer pocket to start with in this incident.

I have communicated with others that had issues using slightly more powder in their testing.  One fellow loaded the 135 grain Nosler over 14.5 grain load and saw 1800 fps and had a casing failure and blown primer pocket...

So with all that in my knowledge base, I am understandably cautious, but have tested the loadings of Underwood as shown in the pull-down section.  Some did produce a "SMILE" as shot by others in Glock and Delta Elite chambers, thus we saw a reduction of Underwoods loadings to be termed "For Delta Elite" 

Cannot be used in Colt Delta Elite or any other firearms with rampless barrel due to complete lack of case support.

With all that said, I do like IMR800X for the power and yield that it does bring to the 10mm and other cartridges, just be careful and observe how it is working with you loadings as fired from you firearms.

[The_Shadow]

Another thing I have looked at is Bullet setback using 800X powder, this further compression of the already max loaded charges will also create the pressure spike.  Remember these semi autos have no cannelure to secure the projectiles with a rolled crimp like that of a rimmed cartridge.  The dynamics of a functioning semi auto are such that a less secure bullet to cartridge fit can push them deeper inside the casing...Set Back.

When I first got the LEE Factory Crimp Die it was going to be used as a finial crimp setup.  However I quickly found out that it did two things I didn't like. 

First was with my Cast bullets as loaded.  It squeezed the 0.4015" bullet slightly smaller in diameter (0.3995"-0.4000") and that allowed the bullet to lead the bore because of the by passing gases.

Second was the tapered ring was such that some casings snagged (maybe longer cases) and buckled.  The bullets were actually left loose in the finished cartridge.  I could twist and turn the bullet as it sat in the casing.  This also could have been in part of the pressing by the carbide ring squeezing it ever so slightly.

So this LEE Factory Crimp Die now serves only one purpose for me, that is as a Pass-Through sizer for 10mm, 40S&W, 357Sig and 9x25Dillon.  It irons the bulges out on the lowest part of the casings were normal sizers do not reach.  It also squeezes the case head slightly, and it has shown to tighten up loose primer pockets and uniforms the roundness of the case head and  extraction rims.   

[Taterhead]

So basically they say that the "think" it could be bad??  Apologies but that's simply a non answer. 

There are reasons for everything. Stopping because they THINK some thing bears the necessity to prove this out. I just don't believe they stopped because of a feeling.

Tell us pressure spikes as is seen with lil gun...FINE! But a feeling???   

CW

I might not have explained properly...

They saw stuff in the lab. The latter part was his SWAG about why the readings were as they were. The reduced charges were the result of lab tests, not a feeling.

[Geeman]

Every powder gets more efficient when the working pressure increases.  800X seems to me to do that more than typical. 

800x shows some big differences in the burn rate charts, from faster than AA5, to the same as Blue Dot.  I think this is why.

I ALWAYS load 800x where there is NO signs of pressure.  I generally get more speed with 800x like that than other powders get running at absolute max.

Its still my favorite 10mm powder, but be careful when getting close to max, and even then, back down when outside temps get warmer.

Greg

[wadcutter]

I've never used IMR Hi Skor 800X, but looking at Hogdgons load data I've noticed they don't give a starting load with this powder. Is it similar to W296 in that it's not a good idea to use mild loads due to the risk of lodging a bullet in the barrel? Hornady and other manuals do give starting loads for 800X but they also have starting loads for H110 although those aren't exactly mild.

[The_Shadow]

800X is originally a shotshell powder it has found good uses in metallic handgun cartridges like many other shotshell powders like Blue Dot...  Not having lower starting loads in this case is because the pressure values for the most part are low for their yield, like that of Blue Dot.  You need a fair amount of pressure to expand the casing outward to seal the chamber...this is why we see soot trying to bypass the mouth of the casings.

if you look over the older IMR data you will see they also only listed single loadings...
http://www.castpics.net/LoadData/Freebies/RM/IMR/IMR01.pdf

[wadcutter]

That's a good explanation and it makes a lot of sense. I knew there had to be a good reason why they don't give starting loads with this powder.

[cwall64]

I know that some loads on Alliant's website that only have a max value say start 10% lower...  I did that when working up my 800X loads and didn't have any issues.  8.7 grains with a 180 bullet got me values in the 1210 FPS range.  I did get higher ES and SD with 800X than I did with Longshot and BE-86.  But great velocities...

[Seabeeken]

Comparing older data to newer could also be differences in production lots of 800X.
My hornady manual #9 shows a max of 10.1 gr of 800X with their 180 XTP

[Taterhead]

Comparing older data to newer could also be differences in production lots of 800X.
My hornady manual #9 shows a max of 10.1 gr of 800X with their 180 XTP

That load data is pretty high, in my opinion. I get pretty wicked excessive pressure symptoms by about 9.6 grains. Noticeable pressure symptoms started in the low 9s. No other published data has give me pressure symptoms except that one. I have done more than 2 dozen unique bullet and powder work ups in 10mm. That has been the only one to show issues.

[bjw0007]

I used the Hornady data for 180 grain to work up some cast hollowpoints (modified Lee 175 TC) that weighed 170 grains with 800x.  9.4 started to crater primers, 9.6 is as high as I got (1380 fps, 720 ftlb).  The max I settled on was 9.3.  About the same range as you Taterhead.

My loads started out at 7 grains of 800x.  The chrono data is pretty linear all the way up to 9.4 grains, where it "hiccups" and doesnt increase velocity from 9.3 to 9.4.  It increases again at 9.5 up to 9.6.

I also noticed a plateau at 1150 fps, but I've seen that in other calibers as well, even at low charges.  I suspect it's the sound barrier, and requires "punching through".

[cwall64]

Heck, I was happy with the Hodgdon data of 8.7 grains at average velocity of 1210 fps (out of Glock G20 Gen4 barrel).

[bjw0007]

8.7 is fine, but in my case I was going for two loads: 600 ftlb and 700 ftlb.  It's good to have a target velocity in mind, and go past it only far enough to make sure an extra 0.1-0.2 grains won't be disastrous.