Show off your 300 AAC rifles!

[Death]

Well I finally got my first .300 AAC Blackout rifle. Bought a CORE15 M4 MOE from Wanstalls. It arrived today so I threw on my Aimpoint CompM2 for now. A couple rounds of Remington Accutip 125gr to sight it in. And then tried an assortment of ammo I purchased. I only played at 25yds. There was a heavy 24km/h cross wind.

Ammo used was:
Remington Accutip 125Gr
Remington OTM Match 125Gr
Remington UMC 115Gr
And Remington OTM 220Gr subsonic

The rifle has a 16" 1/7 twist Stainless barrel with a carbine length gas system. And definitely does not like the 220gr subsonic ammo. It would not eject a single case on the 220 gr.#

The pics are cellphone pics. So sorry for quality

So let's see and hear about everyone else's

 

[VanIsler]

If you want to shoot subsonic ammo, I believe going to a lighter buffer should help.

 

[Davie Sprocket]

Nice I want one of these uppers, but I only bought my core15 last month so I need to get used to the rifle before I go any further with it, maybe after a few hundred more rounds.

 

[cr5]

View attachment 4934

PWS MK109 piston upper with Stag lower.
Lots of fun. Doesn't like factory subsonic but I've built some handloads with 208gr Hornady bullets to try.
It loves 110 v-max with H110 though

 

[8 ball]

Here is mine. These pics are from last fall. It now has a Gen 2 lower, Norgon ambi mag release, BAD ASS selector, and I've taken the BAD lever off.

 

[Suputin]

If you want to shoot subsonic ammo, I believe going to a lighter buffer should help.

The primary problem is the carbine length gas system. Subsonics require a pistol length gas system for reliable operation.

 

[Paulinski]

I agree ^^^

My MRP 16" barrel has pistol length gas system. Cycles 220 SMK handloads with 10.8gr of AA1680....

 

[VanIsler]

The primary problem is the carbine length gas system. Subsonics require a pistol length gas system for reliable operation.

For sure but on 300blktalk people are getting their carbine length gas systems to cycle by changing out their buffers. Worth a try.

 

[cr5]

For sure but on 300blktalk people are getting their carbine length gas systems to cycle by changing out their buffers. Worth a try.

But then wouldn't it cycle too fast when shooting supersonic ammo? Would be very harsh. The benefits of subsonic are lost without being able to run a can so I won't be losing any sleep over it if my last batch of 208gr loads don't cycle. Mine is pistol length piston system though so it may work. Just doing it more to play with different loads because I have the bullets anyway.
I've tried 208gr Hornady 300 Whisper factory loads and they didn't cycle. The upper was brand new that day though so it may have loosened up a little since then. They chrony'd at 900-950 from my 9.75" barrel.

Good luck but I personally wouldn't waste a lot of time or energy messing with your gun to be able to shoot subsonic unless you are one of the lucky ones like Suputin who can suppress. 110-125gr pills cycle great with H110 and are really fun against killer water bottles at 100yds.

 

[VanIsler]

But then wouldn't it cycle too fast when shooting supersonic ammo? Would be very harsh. The benefits of subsonic are lost without being able to run a can so I won't be losing any sleep over it if my last batch of 208gr loads don't cycle. Mine is pistol length piston system though so it may work. Just doing it more to play with different loads because I have the bullets anyway.
I've tried 208gr Hornady 300 Whisper factory loads and they didn't cycle. The upper was brand new that day though so it may have loosened up a little since then. They chrony'd at 900-950 from my 9.75" barrel.

Good luck but I personally wouldn't waste a lot of time or energy messing with your gun to be able to shoot subsonic unless you are one of the lucky ones like Suputin who can suppress. 110-125gr pills cycle great with H110 and are really fun against killer water bottles at 100yds.

Possibly it would be too violent if you shot the supersonic stuff but considering it literally takes 10 seconds max to swap a buffer, I wouldn't rule it out as an option. But as you pointed out there is little benefit to shooting subsonic...perhaps less meat damage with a slower heavier bullet than the faster lighter pills...which of course is moot for us.

 

[f55]

Should i be using a standard or H buffer for 300 blackout 16" for supersonic loads.

 

[2bad4u2]

But then wouldn't it cycle too fast when shooting supersonic ammo? Would be very harsh. The benefits of subsonic are lost without being able to run a can so I won't be losing any sleep over it if my last batch of 208gr loads don't cycle. Mine is pistol length piston system though so it may work. Just doing it more to play with different loads because I have the bullets anyway.
I've tried 208gr Hornady 300 Whisper factory loads and they didn't cycle. The upper was brand new that day though so it may have loosened up a little since then. They chrony'd at 900-950 from my 9.75" barrel.

Good luck but I personally wouldn't waste a lot of time or energy messing with your gun to be able to shoot subsonic unless you are one of the lucky ones like Suputin who can suppress. 110-125gr pills cycle great with H110 and are really fun against killer water bottles at 100yds.

You should try subsonics out of a 16" barrel before you dismiss the idea all together. It's considerably more comfortable than shooting supersonic rounds.

 

[agilent_one]

9"

 

[cr5]

You should try subsonics out of a 16" barrel before you dismiss the idea all together. It's considerably more comfortable than shooting supersonic rounds.

I haven't given up on it just don't care as much as developing an accurate 110gr v-max load.
My upper has a 9.75" barrel. The best part about the 300BLK for me is that it doesn't lose as much on ballistics with a short barrel like a .223 does. I have no interest in going longer unless I can find a good non restricted in 300BLK.
I will develop a load that will cycle with the 208gr Hornady pills (hopefully in the batch of testers sitting in the gun room). I have a couple powders that I bought just for building subsonic.
I WANT A SUPPRESSOR!!! then I'll care more about subsonic.

 

[Death]

Well went out today and shot 60rounds of UMC, 40rounds of Accutip and 20rounds of Match OTM

The UMC blew out 2 primers and an Accutip almost popped a primer

I love the way this Core shoots tho

Accutip at 25yards

And #a mix of UMC (center/top right)
Accutip (top left)
And finally Match OTM (lower left)
All at 100yards with a 15km wind left to right

 

[f55]

Core15 300blk 16" carbine length gas.

150gr btfjm
2.185 not 2.85, 3 touching are about .6" at 50 yards

110 vmax @ 50 yards

Tomorrow will try 11.5gn H4198 and 220gn smk @2.20 AOL

 

[f55]

2 at bottom are 220gn smk with 11.5gn H4198. Accuracy is ok at 50 yards but will not cycle action.

 

[cr5]

2 at bottom are 220gn smk with 11.5gn H4198. Accuracy is ok at 50 yards but will not cycle action.

MO POWDA!
Have you chronographed any of the loads yet? That would be the most help with load development of subsonic loads.

Have you tried AA1680? I hear it's a good powder for subsonic.
I think it was LiL'Gun that was also suggested to me for heavier boolitz.
Suputin is the subsonic expert, if you need load help he would be the best guy to PM.

 

[f55]

The data i can find on 220gn smk is 11.5gn min & max, no chrono till next friday.

I can't find AA1680 which is why i tried H4198.

 

[Diablo9845]

What length handguard is that and what type of muzzle device are you using? I have a 8.5 inch barrel and am looking for the same look as yours, so I was thinking of going 9inch handguard. Trying to decide if I need a solid brake/flashhider so that gas isn't bled off while still under the handguard as the barrel is shorter by half an inch.

9"