Piston upper barrel question

[5.56Geo]

I have an Adams Arms upper and would like to swap the barrel out. Is there anything special about a barrel used on a gas piston system as far as where the gas blocks sits? could I swap it for a Centurion Arms barrel of a different length? If I gave my old AA barrel to a friend would he be able to put a direct impingment gas block on it? Thanks for the help;).

[varmint49]

Barrel length does't matter but the length of your gas hole in the
barrel does.As far as you friend using your old barrel same thing
as long as you gas hole length is the same he can use it.You have
one of three length gas system,( carbine length,mid length, rifle length)
You ntake it from there.

[5.56Geo]

Thank you, I thought there could be some kind of proprietary gas port or hole location(not sure of the name) on the barrel that would only line up on the Anams Arms gas block that wouldn't line up on a milspec gas block. Thanks again!;)

[jet80tv]

A gas block is a gas block as long as your friend gets a gas block that is the right diameter for the barrel profile(.750 or .625 for example) and then the proper length gas tube. If you have a midlength gas port on the barrel and he has a carbine length set up then he won't be able to use his shorter gas tube, easy enough to get a new one. The Adams arms system is a "drop in" system that will work on any. Stripped barrel(that is the right diameter for your AA gas block), you would just need to make sure you get your new barrel with the gas port length as your existing one or you'd have to get a new drive rod

[Suwannee Tim]

I have been messing around with the AA piston kit a lot in the last few months and I say "What the guys above say."