Switched from the USGI to an aluminum with rails. Since it clamps on is there a good way to tell if the gas holes are properly aligned?

TIA

Uh, since you can't see the gas port holes in the barrel nor the block with the gas block on the barrel how can one "line them up?"


Pulling the trigger may be the only way to tell It sucks if it is

This is what I did to solve the nagging question mark in my retentive mind - Take a pencil or a fine Sharpie pen mark the center line of the gas hole onto the barrel where the gas block would stop (use a straight edge ruler if you want to be precise.)  Do the same for the new gas block's backside, where it stops against the barrel step.  Use those markings as indexing points, line them up and you're good to go.

Another way to do it is put a leveler on the receiver flattop, level it in the vise (padded of course), then do the same for the gas block.  The holes should line up this way.

Didn't suck as bad as I thought. I put the block on and visually aligned it. It wouldn't cycle so I hand cycled about 7 rounds. I then removed the block and there was a ring left by the gasses on the barrel. I could see where the block covered the edge of the hole in the barrel slightly. I reassembled and moved the block forward about an RCH and it works fine now.

My goodness, here is what I do.  You plug the breech end of the barrel with a cork, piece of rubber, whatever you can find that will fit.  This may sound eerie to some, but then you blow through the muzzle while moving the block around until you can hear/feel the air escaping through the gas tube.  I know, sounds wierd, looks wierd when you are doing it ( my wife about freaked when she walked into the garage).  Point is it works, you can build it, put it away, and know it will shoot when you bring it out.  I've done this several times, and it's good for a cheap buzz at the same time.

My goodness, here is what I do.  You plug the breech end of the barrel with a cork, piece of rubber, whatever you can find that will fit.  This may sound eerie to some, but then you blow through the muzzle while moving the block around until you can hear/feel the air escaping through the gas tube.  I know, sounds wierd, looks wierd when you are doing it ( my wife about freaked when she walked into the garage).  Point is it works, you can build it, put it away, and know it will shoot when you bring it out.  I've done this several times, and it's good for a cheap buzz at the same time.