300 blackout cycling issue

TGRESCH · Sep 14, 2014

im not exactly sure where to put this but here seemed like a good starting point. I recently traded a couple 200$ shotguns for a .300 AAC Blackout that a guy built for his girlfriend who he broke up with because she had drug problems anyways I was sighting my scope in and i could fire a round but the bolt wouldn't move(no ejection) my father in-law was helping me and he said he could see gas coming out in front of the bolt carrier, so that would lead me to believe the gas black is lined up correctly on the barrel and the head spacing seems to be correct because everything sits flush like it should. So does this mean the gas tube and the gas chamber on the bolt carrier aren't seating correctly or what? any suggestions or thoughts would be great. Also ive talked to the guy and he said if i wanted to bring it over he could look at it but i want some second opinions first.

spectra · Sep 14, 2014

What loads were you putting through it? What barrel is in it? What length of gas system? When it comes to 300 could be many a issue. Also how lubed up is the bolt?

Also look here http://www.300blktalk.com/forum/index.php very good forum.

trevoro · Sep 15, 2014

"So does this mean the gas tube and the gas chamber on the bolt carrier aren't seating correctly or what?"

Have you taken the upper off and cycled the carrier by hand to see if it is lined up?

I had trouble with my .300 like this. I ended up realigning the gas block and it fixed it.

Member 34319 · Sep 15, 2014

Home brew builds are always riddled with issues. Most of them fall directly on the gas system. Chances are the gas block is not aligned. That's my 1st check. 300blk has good pressure at most barrel lengths so chances of it being something else are small. If it's not the gas block. Check the gas tube and make sure it's not damaged in the receivers end. After that your onto checking the BCG. However it sounds like a newer build so I'm going to guess the BCG is in good condition and not gunked up beyond belief.

TGRESCH · Sep 15, 2014

it is a newer build only a handful of rounds and a couple months old. Its carbine length and i know those are prone to have issues i pulled the gas black off and cleaned the tube and made sure it was aligned properly which i would assume would still be proper anyways because the bolt comes back a bit and there is gas coming from the extraction chamber. I did look at it some and the gas chamber thing on the bolt (sorry not sure of the actual name) seems to have a beveled lip about a 16th of an inch smaller than say the one on my AR and it runs about 1/4" long if that makes sense i can take pictures later if that will help

spectra · Sep 15, 2014

Yes carbine length can be a issue. Do you know the gas port size? It might need to made a little bigger.

I know one barrel I have will not cycle with certain ammo if there is not a can not it.

Also look over on that link I posted lots of great info over there.

TGRESCH · Sep 16, 2014

i don't know what the port size is but i was told its supposed to be 7/32 so when i finally get some free time ile check it for sure. one question i do have because im pretty sure my problem lye's within the bolt carrier so im pretty positive it will but would the bolt carrier out of my .223/5.56 AR work for testing purposes?

jbett98 · Sep 16, 2014

Yes it would. Everything's the same except the barrel.

TGRESCH · Sep 16, 2014

alright thank you and that's what i thought but before i blew my guns or myself up i wanted to make sure before i did so

jbett98 · Sep 17, 2014

What recoil spring and buffer are you using?

TGRESCH · Sep 17, 2014

im not sure what the original was but I replaced it(temporarily) due to rust with the one out of my bushmaster AR but i haven't gotten a chance to test that theory out. Doubt its gonna work but ile give it a try.

TGRESCH · Sep 17, 2014

And sorry for the tardiness of the response but the upper has been disassembled multiple times, i like to know my guns inside and out before shooting, lubed up very well because for the most part you cant ever lube to much and initially i was shooting reloads but those sucked and then i was using hornadys which is the only brand i can get around here but they were good and i was able to finish siting my rifle one round at a time. In about a 45 mile radius of me there is one place with these rounds.

bassman2 · Sep 17, 2014

One recommendation I got was to use a NEMO spring and a regular weight buffer.

The NEMO spring is specifically for 300 blackout. Buy at Curts or online....