I am having the same problem my bolt carrier keeps hitting my gas tube.I have built several. I used the adapter to line up the gas tube on the first. Would not line up and the bolt would not go in. Loosened and used the bolt, worked perfect.
When you line up the barrel nut, put the charging handle and bolt in and line ti up that way. The same when you tighten Down the gas block. Should work like a charm.
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