Need advice on 300 blackout pistol not cycling.

[nssauls]

Need help guys. 10.5”, 1:7 barrel. Carbine buffer and spring confirmed at just under 3 oz, 10.5 inches with 36 coils. Gas hole in barrel and tube confirmed at .125. Can’t measure the gas block hole but appears larger than barrel hole. All confirmed clean and clear. Will cycle with supers over 2000. Will not cycle with subs at 1050. Today I tried a 180 grain load at 1300. Did not cycle. I changed the BCG out today thinking the bolt rings might be bad. No change. What am I missing?

[UH60_TrunkMonkey]

Did I miss the gas system length?

Most 300blk subsonic need a pistol length gas system. They can be made to cycle with carbine gas but I'm not sure how.

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