LRBHO Failure - Stumped

[VASCAR2]

Generally if the bolt is not captured by the bolt catch and is held back by the magazine follower there is insufficient recoil momentum. The bolt and carrier are not going far enough back to permit the bolt catch to rise and stop the bolts forward momentum. A sticky bolt catch could contribute to the failure to lock back the bolt. I’ve had to polish one bolt catch as it was very sticky and didn’t move freely. Like someone else mentioned I’d also measure the inside depth of the buffer tube.

The solution might be to open the adjustable gas block a little more with that particular lower.