Suppressed AR-15's with carbine length tubes and fast powders.

arlaunch

arlaunch

Active member
Hello all,

My silencer is supposed to arrive in just 2 short months and i have been building up a new rifle for it.

The barrel is a 16 inch Colt 6721 with a 1/9 twist. The rifle has a carbine length gas tube with a JP adjustable gas block

I have been thinking of ways to make the rifle shoot more clean. I have also been thinking of ways to slow/tame the bolt unlock a bit in addition to the other know easy solutions that are installed in my rifle at this time such as a heavy buffer and a superior shooting systems buffer spring.

I will primarily shoot 55gr Nosler BT's, Sierra #1390's and Speer 55sp's.

I am looking for a powder that shoots accurate on top, shoots relatively clean and can obtain my target velocity range of 2875fps - 3000fps + out of a 16 inch barrel.

I have a lot of experience reloading with heavier bullets, slower powders and longer barrels. I am mostly thinking of port pressures here on a carbine length gas system that has a suppressor.

I am looking into these selected powders and more:

Power Pro Varmint
Reloader 7X or 10X
A2015
IMR 3031
Benchmark
H322
A2230
H335


I have 10+ different types of powders on my bench that i use for different rifles etc. But i have never used these. (except a batch of 3031 that was old and garbage)

I understand that velocity could be higher with the more popular, slower burning types i have on hand.

I am looking for a special powder that will be winding down and burnt up by the time it makes it to my gas port. Yet also deliver excellent velocity.

In general i have found that long gas tubes & heavy bullets for the powder burn rate keeps the receiver, magazine and BCG nice and clean.

My 24 inch Colt 6724 shoots so clean with W748 i can't believe it.

At this time Benchmark, A2015 & RL 10X are on my high list.

I will post back my results, trials & tribulations when i come to my final load for this rifle. It just could end up being a slower powder than listed? Time will tell.


Thanks in advance for the advice if you have any quality input,

A

 
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Just a follow up to this thread. I just did not have the time or energy to test and test.

I started and finished with Sierra 1390's.

My best results were:

26.7 - 26.9 grains of W748 with WSR primers at 2810fps. Excellent accuracy.
25.6 - 25.8 grains of AA2230 with WSR primers at 2875fps. Excellent accuracy.
26.1 grains (shoots sub MOA in a large range) of H4895 at 3010fps. Excellent accuracy.

All these loads shoot great. I went with H4895 and CCI #41 for the velocity. Already took a Coyote with this new load last week.

I don't see changing loads anytime soon. Though i am sure there is a better one out there. I have turned the adjustable gas block down to just barely lock the bolt back on the last. It cycles so smooth i don't blink.
 
So I take it you ya e your surpressor now? Sounds like you got a good shooting gun. Shooting an ar15 surpressed is nothing clean about it in my experience. I shoot my 6x6.8 ar15 surpressed also and just have to clean my bolt carrier more often then with out one. Not really to big of a deal.
 
I'd give H322 a try, my rifle while not suppressed(18" barrel rifle gas) it takes considerable more gas to reliably lock the bolt back with h322, compared to cfe 223, it also has a heavy buffer.
 
Originally Posted By: arlaunchJust a follow up to this thread. I just did not have the time or energy to test and test.

I started and finished with Sierra 1390's.

My best results were:

26.7 - 26.9 grains of W748 with WSR primers at 2810fps. Excellent accuracy.
25.6 - 25.8 grains of AA2230 with WSR primers at 2875fps. Excellent accuracy.
26.1 grains (shoots sub MOA in a large range) of H4895 at 3010fps. Excellent accuracy.

All these loads shoot great. I went with H4895 and CCI #41 for the velocity. Already took a Coyote with this new load last week.

I don't see changing loads anytime soon. Though i am sure there is a better one out there. I have turned the adjustable gas block down to just barely lock the bolt back on the last. It cycles so smooth i don't blink.



Good deal! I've always had good luck with 4198 and 4895 (both IMR and Hodgdon). I don't use a suppressor, but I have always found them to be very accurate and clean burning.
 
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