Originally Posted by mjkeat
Would a torpedo level work?
Yeah, I suppose so, but man. The little vials I picked up from my LGS are SOOOOO freaking handy. For the $10-$20 I spent they've saved me hours of frustration.
But you had said something that made me think. . . about the extra little turn to get the gas tube to line up (which is always a pain for some reason). . . Anyways, It would be a good idea to make a center-line (reference line) on the barrel in line with the port before installation of gas block. So
to double check yourself after leveling off of the receiver, Make a second center-line on the gas block (visible from the top angle). If those 2 lines are in line and the receiver and block are both level, then you know you're dead nuts.
Maybe a little excessive, but
I had a guy install a block on one of my carbines (short on time that day and had to get out of that store). The gun test fired just fine, locked back and all, but about 80-120 rounds into the session my vert-grip and front, lower hand-guard came off in my hand!!!
The block must have been ever so slightly off-center and shot itself loose. I fixed it out there and shot some more, but re-aligned it at home later the way I described.