14.5 barrel and gas system

[itotorica]

I'm in the process of building my second rifle.My choice is a 14.5 barrel but I'm not sure of what gas system to chose.
What are the benefits of the mid length over the carbine length?
Thanks

[YVK]

Subjectively softer recoil impulse (not by much), lower operating pressures - theoretically longer parts life (not proven to any extent scientifically) with midlength gas system. If you go with FSB, the carbine will mandate shorter handguard - which has its own pluses and minuses.