Help! Should my AAC 300 carbine upper reliably fire from an AR that's got a rifle buffer tube

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[ARCHIVED THREAD] - Help! Should my AAC 300 carbine upper reliably fire from an AR that's got a rifle buffer tube

Posted: 8/28/2015 12:20:48 AM EDT

I have a Seekins AR15 set up with a rifle length gas system and buffer/fixed stock. I also have a 16 in. AAC 300 Blackout carbine upper that I'd like to use with the Seekins lower. Should it fire "reliably" given the lower has a rifle buffer tube, or do I need to have a carbine buffer tube? 300 ammo is too expensive to just try it out at the range. Thought I'd see what you think before I waste what little ammo I have.

Posted: 8/28/2015 12:29:40 AM EDT

[#1]

I have heard of people making it work, but I have my doubts.

Posted: 8/28/2015 12:42:14 AM EDT

[#2]

NVM...wrong thread...

Posted: 8/28/2015 1:59:02 AM EDT

[#3]

Gas system length and receiver extension length are completely unrelated.

Posted: 8/28/2015 9:18:24 AM EDT

[#4]

Thanks for the input, I just hate to waste ammo. It's not as expensive as it is hard to find on the shelf at the big retailers. I'll give it a go with the cheapest rounds I have first and post feedback. Someone replied that this was the wrong forum for this post, if you could kindly direct me to the correct forum that would be greatly appreciated.

Thanks, HkCarr

Posted: 8/28/2015 9:21:18 AM EDT

[#5]

Me too, especially with the lighter super sonic rounds. The heavier subsonic may provide enough recoil to cycle the action reliably. Then again they are loaded weaker as well, so guess I have to go throw some lead downrange to find out. I guess there's worse things we could have to do, huh?

Posted: 8/28/2015 10:20:44 PM EDT

[#6]

Check out Ozark Ordnance for affordable and readily available 300 ammo.

Posted: 9/16/2015 5:07:38 AM EDT

[#7]

I also have one of those AAC 16 inch uppers. Their web-site contains a note that says:

IMPORTANT NOTES:
-The 9" and 12.5" AAC 300BLK Uppers are designed for use with a carbine receiver extension, standard GI Buffer Spring, and an H2 Buffer.
-The 16" AAC 300BLK Upper is designed for use with a carbine receiver extension, standard GI Buffer Spring, and a CARBINE Buffer.

It seems pretty clear AAC doesn't recommend the use of a rifle receiver extension and buffer.

Posted: 9/16/2015 6:19:34 AM EDT

[#8]

Pushing almost another 2 oz. with the rifle buffer, probably not even with supers. Subs ... not a chance.

Posted: 9/16/2015 10:19:19 AM EDT

[#9]

It should work fine. The rifle buffer tube with the correct rifle spring and buffer is approximately equal to a carbine tube with a carbine buffer and corresponding spring. 2oz heavier rifle buffer is offset by a completely different rifle spring designed to work with that buffer.

With that said, subs are finicky and it wouldn't surprise me if they didn't work in any new lower or buffer setup. On paper it should be fine, give it a try.

[ARCHIVED THREAD] - Help! Should my AAC 300 carbine upper reliably fire from an AR that's got a rifle buffer tube

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