.300 blackout ejection issue

[Kyle Klinger]

I have a .300 blackout with 16 inch barrel running an omega 300 on it. It was cycling supersonic fine but wouldn’t cycle subsonic. Now I have run into the problem where it won’t cycle supers. This gun has turned into a single shot have to rack after every shot. I’ve taken it apart and cleaned it.

What should I do? It ejects the shells when racking the gun. So is it a gas problem? If so why was it running supers fine than it stop cycling.

 

[David's Gun Room]

what do the malfunctions look like? could be gas block, could be extractor issues, could be rsa, could be other random ****. kinda need more info on what the malfunctions look like to drive thru diagnose it. Being a 16" gun need to know what length gas system as well. I love .300 blackout but it really is a specific system that needs scrutiny to run in peak shape. I was having this conversation with a customer yesterday.

 

[Kyle Klinger]

After shooting a round the shell doesn’t eject. Try to rerack the gun and it is hard to rack. Almost like the shell is expanding inside the barrel. It has a mid length gas system.

 

[Dirty J]

I’d be checking to see if the gas block has come loose first off.

If it was working with supers and now it’s not… something has changed/broken for sure.

Work the gas system front to back. Gas block alignment. Check carrier key tightness. Etc

 

[Kyle Klinger]

what do the malfunctions look like? could be gas block, could be extractor issues, could be rsa, could be other random ****. kinda need more info on what the malfunctions look like to drive thru diagnose it. Being a 16" gun need to know what length gas system as well. I love .300 blackout but it really is a specific system that needs scrutiny to run in peak shape. I was having this conversation with a customer yesterday.

Replied above I forgot to tag you

 

[David's Gun Room]

So brass stays in chamber? I would agree start with GB then gas tube and work your way back, with an analysis of the BCG following, followed by checking buffer weight, recoil spring weight (doubt it is this but still should be assessed). also compare supers/subs with and without can.

 

[cmshoot]

If you can bring it by TruPrep in Marietta I’ll be happy to diagnose it.

Are the supers that it won’t cycle with now the same supers that it used to run with?

If it’s a 16” with a midlength gas system, I would say it is never gonna reliably run subsonics, with or without a can. You need a pistol-length gas system for reliable subs.

Gas block could have shifted, which would make it stop cycling, and the shifted gas block could move the gas tube enough to cause it to hang up in the BCG and add difficulty to cycling by hand. Shifted gas block is the most common issue I see when a gun that was running fine, suddenly stops running.

Faulty BCG is one of the most common issues I see in AR’s today. There are far more crap BCG’s in the wild than there are decent ones. Most of those aren’t even worth trying to fix.

I have seen various issues which can cause the BCG to drag; upper to lower fit, buffer retainer, receiver extension, bits n’ pieces in the lower receiver, etc.

 

[Control for Smilers]

Do you have a spare BCG you can test with. would look there first. cmshoot beat me to it.

 

[Joe Mama]

Saw on another forum the gas key on the carrier was so cludged with carbon that it caused something similar.

That wasnt part of his normal cleaning regimen and it added up.