We are now upgraded to the newest version of phpBB. It has more features. Enjoy.

If you've forgotten your password or are having trouble logging in, CLICK HERE for a reset password to be sent to you.

300 Blackout AR

Anything to do with rifle shooting, plinking, target, benchrest etc

Moderator: Moderators

User avatar
Marksman I
Marksman I
Posts: 8
Joined: Wed Dec 19, 2012 1:00 am

300 Blackout AR

Postby Droopy » Mon Apr 29, 2013 10:12 am


I saw a post on 300BlkTalk regarding a possible short-stroking issue. One of the replies was from ChrisNCT- Hoping he or someone here might have an opinion ... no really ...

I recently built a 300 Blk AR;

16" CMMG - carbine gas port barrel
Troy Medieval MB
Spikes Upper and Spikes BCG
Rifle length buffer tube, buffer and spring
Generic AR lower

I first did all of my function checks with Remington factory loads - 115gr using 20 rd P-mags - and all was well.

This weekend I picked up some hand loads from a reloader - 147gr. Some of these were made from 'cut' .223 cases and some once used 300 BLK cases. This time I used 10 rd metal magazines as I had heard that feeding could be more reliable.

However I had real issues. The rifle would not chamber a 2nd round, either it wouldn't pull a cartridge from the magazine at all, or it wouldn't load the cartridge completely into battery. I had a couple of jams where the bolt was mostly forward but 'locked', I had to 'gorilla' it to open the bolt. Pretty sure that was all a result of short-stroking.

I was going to try some sub-sonics (220) just for giggles to see what kind of impact those would have, now I'm not so sure I'll attempt that. (TMI) I'm waiting for my SBR stamp - went pending Jan. 3 - and suppressor stamp - mailed a little over a month ago, still not pending ... anyway, that was planned to be a similar setup to the 16", but with a 10.5" pistol gas port barrel. Now I might need to rethink that also.

I did see a mention of 300 BLK preferring a carbine buffer - I built the rifle length since I would have have to pin an adjustable carbine stock or go with an entry stock which I find too short ... gotta love CT - I'm thinking the 147 gr was just enough to keep me from cycling as compared to the 115 gr ... in my particular setup.

I am going to talk with the reloader, but, before - wait for it - I go off half cocked - just wondering if anyone here has had a similar experience.

Thanks for reading

User avatar
High Master II
High Master II
Posts: 2434
Joined: Sun Feb 03, 2008 1:00 am
Location: SE CT

Postby CTSixshot » Mon Apr 29, 2013 12:59 pm

I'd verify with the ammo maker as to whether he used a headspace case gauge to check his brass. You could end up with issues like you mentioned with improperly sized/formed brass.
Beyond that, I don't shoot that caliber, so I can't say much else.

Return to “Rifle”

Who is online

Users browsing this forum: No registered users and 5 guests