10mm loading and testing

[John A.]

I really enjoy pistol cal AR's.

There's several different styles these days. Originally, there was only blowbacks. Which all of mine are. Now, there are DI and even CMMG has their rotary delay that they call the banshee which is more like a standard AR bolt which is supposed to be great. But, those are expensive and hard to get.

But, I like pistol caliber stuff.

 

[tcecil88]

I have a Freedom Ordnance FX-9 that shoots great, but just have never built on for myself. Back when I was thinking of building one, seems like alot of the parts would not play well with others, so I just bought a factory built one. I wouldn't mind building an Aero Precision EPC, but just never got around to it. I see that Aero has a 10mm/.45 acp version coming out soon, so I may look into it then.

 

[John A.]

It's not that much different really. Some, but not as much as one would think.

Use a heavier buffer tuned to the loads you're shooting. That's the biggest thing.

 

[nitesite]

The #9 powder with 155 gr xtp hornady was by far the most impressive speeds.

15.9 gr no. 9 powder
155 gr xtp
1.25" col

1748
1750
1780


1769 fps ave

1077 ft lbs
----------------------------------

Pretty impressive results with #9 and that bullet. Great job, John.

Was that brass new or used, and did you get any case bulging? I would think that a slow burning powder like #9 would be pretty easy on the brass unless you have really crappy case support.

 

[John A.]

No, that was with some of the SPP brass.

I haven't opened the sealed bag yet, but I have shot some of the LPP brass that was loose and they're doing well. I haven't checked the velocity of them though compared to the others. I wouldn't suspect they would be very different.

No case bulging. They shot really good.

But, as I mentioned, this load has very healthy ejection, which I'm trying to tone down some.

 

[nitesite]

SPP 10mm brass is the debil......

Please tell me that I didn't give you any by mistake.

 

[John A.]

No, my friend Buddy had given me a handful to first get me started. I think about 20 or 25 pieces.

It's not that bad to load in my opinion. I can't really see much, if any difference other than which primer it uses.

 

[nitesite]

I just hate that, like some Speer .45 Auto brass, that you could get jammed up during the priming step because you were doing LPP and got a piece of brass that was SPP.

You're correct that performance wise there would be no difference.

Just have to examine each piece of brass for primer size.

I never had to do that with, say, rifle cartridges or .357 Magnum brass etc. Only the 10mm and the .45Auto are the devil child when it comes to primer size, and they are both only recent developments.

Can you imagine if you had .223 brass that could take either size rifle primer? Or .30-06 brass that took small rifle primers? In my mind such a thing would be total bullshit.

 

[John A.]

I don't disagree.

I have already separated the spp and lpp brass.

And I have found some of both in 45acp too.

 

[John A.]

I finished the buffer mod today. I made the sleeve about 1/2" longer than where the location was on the OEM buffer. If anything, will just cause the gun to short stroke. Maybe from not letting it go rearward enough, or perhaps maybe from causing too much pre-load on the spring.

But, I can always slide the sleeve off of it and shorten it to match the OEM location if that turns out to be the case. But I'm hoping that it simply just calms the ejection down some. That's the whole purpose to swapping to a rifle length buffer is to allow it a little more room for travel. And of course, I like the longer LOP too. So, win / win.

I also weighed the buffer. As it sits right now, if I don't have to remove any of the sleeve length, it's a total of 12.35oz.

yes, I know, that's heavy as heck. But, when you're loading to max charges on a blowback action, it takes a little more to keep things in check. That's about exactly double what a traditional A1/A2 rifle buffer weighs.

 

[nitesite]

Pretty awesome skills and knowledge you have my friend.

 

[John A.]

Thanks buddy.

Now, if it just works as I hope and brass isn't launching 14 feet away. All seriousness, that's about how far it's ejecting now.

And why I'm trying to increase the load on the spring and such.

I'll be sure to keep you posted how it does. The A1 tube and foam cover has shipped. So, with any luck, I'll know by this weekend.

 

[John A.]

Haven't been able to test it yet. No way of knowing whether I'll need to replace the spring with another, but I sure like how it feels. I don't believe that it looks too bad either. I know that looks is subjective and the eye of the beholder and everything, but I don't "hate it".

 

[John A.]

Tested today. It was great.

Ejection distance is drastically reduced to about 9 feet now which is much better than before. I feel 9 feet is acceptable considering that I'm loading to max. The gun felt better too. The gun was not only softer and smoother shooting in regards to how it felt, but the whole gun felt more stable and the muzzle stayed a lot flatter too.

While I could add more buffer weights and such, I don't feel it's needed or necessary now. And risks adding too much which will batter the parts, and possibly make it unreliable as well. So, I'm going to call this project :

D O N E.

Now, I need to load up a bunch of rounds for it.

@nitesite do you happen to have any good load data for a semiwadcutter hard cast 175 gr pill? I'd like to work a few of them up. I'm unsure if they'll cycle in the gun, but if nothing else, I could hand chamber them in my gun for when I'm hunting for the first shot, since that's the most important one I'll ever take. I could always load up something else in the mag behind it if I needed a followup shot, but I prefer pass through penetration.

These are the ones I'm talking about:
https://www.midwayusa.com/product/1010743792?pid=838877

 

[nitesite]

Lyman #48

 

[John A.]

Thank you very much.

As it would happen, I don't have a single one of those powders LOL.

 

[nitesite]

Aww shucks.

What do you have in the AA#7~AA#9 range, or Power Pistol? Even 2400?

 

[John A.]

I have some #9. #2. Enforcer. Titegroup. BE-86. Longshot. Those are some of the things I've used for some of my other loads I've worked up.

Well, not the #2. I can't recall ever using it. I'm not even really sure what it's recommended for. I probably bought it for 9mm. It's right next to n320 viht. Which is a good powder for 9mm subs.

 

[nitesite]

Well, AA#2 is right there in burn rate with 700-X which is shown in those tables. You could easily work up some 10mm loads with it even though it is a pretty quick powder. Worth experimenting.

Surely there is some Longshot data out there for 10mm and your cast bullet.

 

[John A.]

There isn't any at hogdons data page.

But, they don't have every possible combination known to man either.