Bolt catching on bolt catch .

[montana]

The bolt catch should not touch your extractor..The bolt catch will catch the lower two bolt lugs.. Your barrel is .0938 and Lilja 20" barrel specs out at .093, so your gas port seems just right. I would check your gas key, gas block, etc for gas leakage.. What bolt carrier group do you have?? All bolt carriers are not made the same. The bolt tail vs the firing pin chamber dimensions can create gas leakage, if the differences in diameters are great..Did you check your gas tube button with a gauge?? Is the gas tube cracked?? There could be friction "binding" in the lower receiver buffer tube, off center barrel extension, leaking gas block, gas key, under power ammunition,ruff or short chamber or throat, etc..