Are most of the roll pins for gas tube/block the same dimension wise? I have a spare pin that came with my carbine length gas tube and wanted to use it in a midlenght tube and yhm setscrew block. I am having a rather difficult time installing it however, its seems more difficult to install than the bolt catch pin. Is there a good tool to use for it? I've used everything I have with no luck. Any help is greatly appreciated

Gas tube roll pin should be .312" x .081". I have found some that vary in size. And yes they are a PITA to get in sometimes. You need 3 hands. Ask someone to tap your punch with a hammer while you hold the pin and punch straight. Small taps should get it started. Once you do it a few hundred times, it gets easier.

Thanks! On the 500th tap it went in a little, 7,000 and itll be golden

There is a roll pin guide tool for this situation. Sorry I forgot where I saw it advertised.

What I do it run a #2-56 (size #2 and 56 threads per inch) tap in the hole for the pin and thread in a #2-56 Allen head bolt. That way no more broken/bent pin punches trying to remove /drive-in that miserable little roll pin.
One problem is that you have to slightly open up the hole in the gas tube. I do not have the drill size easy to get to (and of course it is not a easy standard drill). I think it is .090" . You could probably open up the hole for the roll pin with a awl (from each side).

Oh... one more thing: Buy two #2-56 nuts to go with the bolt.  Once you thread the hole and see the bolt is just a little too long you use the two nuts to hold the bolt in the vice while you trim the bolt to the correct size. Then removing the bolts will clean up the threads.

Its a roll pin, find something
Start the pin then use adjustable pliers and squeeze it in