AR in 300 BLK

[SAWgunner87]

Thinking about building an AR in 300 AAC BLK. Anyone with experience with this round, input and opinions would be awesome. Thanks

 

[slowkoop]

I'm about to start building a 300 blk ar. There's a lot of info on the round at ar15.com. The round was designed so that only the barrel needed to be changes to fire in the ar 556 configuration, so it uses the same bcg as 556. The round was also designed to be shot suppressed, from what I've read there seems to be some problems with a longer barrel over 14". From my understanding you need to have a selector gas block when firing subsonic rounds unsurpressed or vis versa. I didn't read much on that because my build is a sbr.

 

[jgreco15]

I'm about to start building a 300 blk ar. There's a lot of info on the round at ar15.com. The round was designed so that only the barrel needed to be changes to fire in the ar 556 configuration, so it uses the same bcg as 556. The round was also designed to be shot suppressed, from what I've read there seems to be some problems with a longer barrel over 14". From my understanding you need to have a selector gas block when firing subsonic rounds unsurpressed or vis versa. I didn't read much on that because my build is a sbr.

The round is not designed specifically to be shot suppressed; it is a very good candidate for suppressed fire. Longer barrels are not a problem at all. SAAMI specs call for a 16" barrel but this round works very well with barrels in the 8-12" configuration. Not everybody has the ability to own a SBR, though.

OP, I have an 8" 300BLK AR and I absolutley love it. Supersonic is supposively more effective on barrier destruction than 5.56, it works well in short barrels and it makes a great suppressed round. My 5.56 uppers are strictly just for training now for use with cheaper ammo. It helps a lot if you handload but ammo prices for 300BLK are getting down further every day. Right now, I think Ritchies Pawn has the cheapest price on 300BLK UMC from Remington at $10.80/20 round box. What else would you like to know? Lost of good info at www.300blktalk.com

 

[slowkoop]

Thanks for clearing that up, I was under the impression that the round was meant to be silence from the name black out. Very useful information.

 

[Sugarbug]

So I have a DD M4V7 chambered in 5.56... I can just get a 300blk barrel for it and I'm good to go?

 

[cnodie1]

Yes. You can use the same mags too but only loaded with 20 rds because of the extra weight

 

[Sugarbug]

Yes. You can use the same mags too but only loaded with 20 rds because of the extra weight

That. Is. Awesome.

 

[FishingFool]

from the website:

This system was developed to launch 30 caliber projectiles from the AR platform without a reduction in magazine capacity and compatible with the standard bolt.

A buddy of mine just got the dies to make his own brass. I'm going to pick his brain later on this month on how thats going for him.

 

[Vanilla Gorilla]

I haven't found this to be the case at all. My 30rd Mags hold 30rds and function fine.

 

[goteron]

20Rnds? You can load a mag up to 30 rnds with 220g subs and it works fine. Its heavier, but it functions as designed. PMAGS may need to be modified with the heavier / longer rounds.

 

[cnodie1]

Sorry I heard the 20/30 rd thing a long time ago and never looked into it. Good to know though

 

[Sugarbug]

Ok. So I've read that for the blackout barrels, you only have the option of the carbine or pistol gas. I have the midlength DD M4v7... what more do I have to swap out to get one to work?

 

[goteron]

If you get a 16" Barrel, just call DD and get the 16" Carbine Length 300BLK barrel.

Its really a round designed for SBR's. I would definitely not own one with a barrel over 9"