Probs w 10.5” 300 BlkOut upper

[krw]

I have a 10.5”, pistol gas system, Odin adj gas blk.
It will run 110Vmax w 20gr LilGun like a champ. But it has issues w subsonics. I am using 208amax w 10.3gr 1680. I have the gas blk opened all the way? Do I need to buy bx factory subs to try w it? It will lock bolt back on last shot. Any suggestions?

 

[Strykervet]

I don't use adj. gas blocks and I don't have issues. The Noveske SBR barrels run like raped apes supers or subs, can or not, 8.5" or longer with the JP Ent. FMOS BCG's and standard shit for buffers, etc. All I use are handloads and 1680 is what I think I use for 220 SMK's.

What problems? Is the buffer weight appropriate? Try a lighter one? Having a few buffers and different springs can be handy. Where does it eject the brass, supers and subs? Lubed well? Using a can or not, if so what kind and does it provide much back pressure or no? Is it maybe a magazine or an extractor problem?

There's a plethora of things I can think of that can cause problems with an AR, need more info. Be more specific.

 

[hlee]

What do you define as "issues?" Not ejecting? Not extracting? Not locking back on an empty mag? Some combination of all 3? Other?

I have a 8.5" 300 blackout with the Odin works gas block. It does not lock back on empty with the factory Remington 220 OTM subs. Nor does it lock back on factory hornady 208 AMAX subs. It does lock back on all of the factory supers that I have shot.

My notes say that everything from 10 to 10.8 grains of 1680 locked back with both 208 and 225 gr AMAX hand loads.

As for suggestions, more powder and/or more bullet weight. How much lube?

For the record, 10.8 grains of 1680 is barely running 900 fps out of my gun with 225s, less with 208s.

 

[krw]

I run it lubed wet, suppressd Omega. It ejects at 3 Oclock w subs. I run Colt 20rd mags. It has more issues w 20rd Pmags. I have never changed the buffer or spring. Tomorrow I will ld up some up to 11.0grs 1680. It just does not run dependable w subs, but more powder cood solve my issues

 

[Darqusoull13]

So a couple of things to look at but it would really help if you defined the "issue" or better posted a picture. That can narrow down what folks will suggest.

-Start with the problem mag. Hand strip from a full mag and see if the spring is feeding rounds up quickly. If you notice a slow feed you could have issues with long subs binding in those mags. For reference I prefer metal mags (DSG in my case) for 300 BLK subs.

-If it's locking back I'd assume you have enough gas, gas block all the way open and assuming that's centered you should be good there.

-Factory subs are an OK test but that will really only tell you whether you're cycling that round or not.

My build uses a JP FMOS carrier and standard SCS with a 10.5" pistol gas barrel. Cycles supers and subs both unsuppressed and with a Dead Air Sandman K suppressor. Definitely one of my favorites!