I have an Armalite gas block with the weaver top on it. I will be installing this next week and want to see if there are any tips to get it on straight. Since it has screws for tightening and not pins, it seems it could go on crooked. I know I can eye it, and check to be sure the gas tube is connecting with the carrier key properly, but I want to be sure it is right the first time. Any tips?

I put a block on an AR-15 I have a year or so back and was concerned as you are about getting it straight. Mine was the low profile type without anything on it so scope was unobstructed. After all that worrying, it was a piece of cake. The screws centered mine up perfectly by eye. You will get it right I'm sure. Just take your time.