It's In The Works: .375 Socom for AR-15!

[Dawico]

So the anvil is backwards and the cup is gone.

I think when the cup flew out the anvil flip over and got jammed back in the pocket. No way to prove that though obviously.

I just don't think it would fire with the anvil in backwards.

A piece of debris on the bolt face could have hit the primer before lock up causing it to fite prematurely.

But we may never know. Glad the damade was minimal.

 

[ROGER4314]

Thanks!

There is no question about:
The anvil was in the hole backwards.
The primer cup was missing.
The powder for the most part was not ignited.
The cartridge burst absolutely occurred outside of the chamber.
Damage was limited to the magazine and the dust cover spring.
Primer anvil almost totally obstructed the cartridge flash hole. The little tip where the priming compound sits on the anvil was stuck in the flash hole.

Where did the bullet and the primer cup go? Brass looked like an exploding cigar. It was classic!

These SOCOM cartridges must not be tossed in the action and chambered by releasing the bolt carrier group. Warnings about "slam fires" are posted. You load a 458 Socom and .375 Socom round only from the magazine. OK.....if a slam fire occurred, the powder would have ignited, Yes?

I'll listen to any theories!

Flash

 

[ROGER4314]

Made a mistake in an earlier post that I'd like to correct. .458 Socom is NOT a SAAMI endorsed caliber. It is still a proprietary cartridge and is not listed, tested or advertised by SAAMI. Regardless, the .458 Socom turns the AR-15 into a cannon!

On another subject, I took that .375 Socom Kaboom cartridge home and examined that primer anvil under good light and a magnifier. I dug the anvil out of the pocket. An anvil has little feet that rest on the bottom of the primer pocket. It also has a tip where the primer media rests before it is squashed under the cup. Big as life, that anvil was upside down in the pocket! Go figure.........

Flash

 

[ROGER4314]

Last Friday, one of our co-workers (Matt) took the test gun to the range to try out the .375 Socom loads. Matt was a Military marksman. The rounds tested were 175, 200 and 225 grain bullets. All loads were supersonic and the suppressor was removed from the rifle.

Remembering that this is a 10 1/2" barrel, the results were exceptional! Each of the loads grouped within the head area of a standard Human profile target at 300 yards!

The next tests will be with the same ammunition using 16" and 20" barrels installed on the same rifle.

Stay tuned. There is real potential, here!

Flash

 

[Mikewood]

What do you predict terminal ballistics to be like? Waiting in the ballistic gel tests.
Try the 235 grain speers.



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[ROGER4314]

It's interesting that you asked this now. That's exactly what we've been kicking around. In fact, Matt suggesting that we place the Chronograph at the 300 yard mark and get actual velocity.

I've had considerable experience with my Oehler Chronograph and know the risks. When the guys asked if they could use my Chrono at 300 yards, I said "Nope!"

One of our team ran the down range ballistics a while back. They'll give you an idea about the energy and velocity:
Bullet weight: 200 grain
Zero: 100 yards
Velocity at 50 yards 2055
Velocity at 300 yards: 1422
Energy at 300 yards 898
Drop at 300: -26.8"

Bullet weight: 250 grain
Zero: 100 yards
Velocity at 50 yards 1891
Velocity at 300 yards: 1406
Energy at 300 yards 1098
Drop at 300: -30.7"

Bullet weight: 300 grain
Zero: 100 yards
Velocity at 50 yards 1599
Velocity at 300 yards: 1362
Energy at 300 yards 1235
Drop at 300: -61.4"

The Ballistic Coefficient of these bullets is about like a brick. They have a large diameter, squatty shape and large frontal area.

Flash

 

[ROGER4314]

This project keeps getting better by the day! Jim took out the .375 Socom 10 1/2" rifle with silencer and fired a three shot group at 100 yards that a 50 cent piece would cover! I built 52 rounds with 325 solid copper segmented projectiles and an incredibly small charge of 700X powder. The load was recommended to us by the guy who is working up the rifle barrels. I was skeptical at first, but those rounds really shoot well!

This has been my first foray into subsonic shooting and I'm learning a lot!

Flash

 

[ROGER4314]

Jim and I went out to his Liberty County property this afternoon and had a great time!

We fired a real mixture of different rifles and one pistol:
Two .300 Blackout SBR's with silencers.
.458 Socom SBR with silencer.
Another .458 Socom SBR with different brand of silencer.
.375 Socom SBR silenced.
USA made AK-47.
Glock 17 with threaded barrel and silencer.

It was extra fun for me as I chose to shoot offhand (standing) like we did in NRA competition. I quit competing when IKE hit but still did quite well. On one target, I shot 3 rounds of .458 Socom offhand and scored 29/30 with 2 X's. It was the first time I ever shot the rifle and after a long layoff from offhand. It was just 25 yards, but I'll take it!

Flash

 

[ROGER4314]

We had a layoff while we got resupplied but we've developed some outstanding loads for the .375 Socom with supersonic and subsonic with silencers.

We got some custom made copper bullets with ballistic tips and these ought to be fantastic performers. There is now a pile of about 1000 .375 Socom cases on the bench and we're going to work as a team to get them processed.

The last run of 250 rounds tore Hell out of my shoulder and left my right hand with a huge bruise! It's teamwork from now on!

Flash

 

[TonyRumore]

We had tried both Trail Boss and VV N32C (Tin Star) and both had pretty wild velocity variations with the 325gr Maker subsonic expander bullet. Switching to IMR 700X fixed the problem.

Tony Rumore
Tromix

 

[ROGER4314]

Yes, we have been using your data and also changed to 700X. Jim at TBT keeps in close contact with you and I've been loading all of the ammo that we test. This has been a team effort and your input has been extremely valuable!

Sizing that brass torpedoed my right shoulder, so we took a break and I've been teaching the TBT folks how to reload on a Rock Chucker.

We aren't ready to make our findings public, yet, but the whole project is designed to make that .375 Socom rifle available for hog hunting.

Flash

PS. Thanks again for your help!

 

[ShadowDelta]

This cartridge interests me. I already have a 458 Socom SBR and can so this would work with my current can.


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Look up the 375 Yeti...its my next crazy thumper gun

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[ROGER4314]

The 375 Socom has produced high performance and great accuracy in Rifle length, SBR's and in suppressed rifles. It turns the AR into a real blaster!

Yes, I am also a great fan of the 458 Socom!

Flash