RECCE 16" upper?

[Shazam]

I was toying with the idea of building a 16" RECCE or SCOUT upper with an MI extended free floating quad rail. Shmidt & Bender Short dot 1x4 optics on Larue mounts.

Since here are two available gas systems for the 16" bbl can anyone shed some light as to which would be more reliable? A Carbine gas system or a Mid-Length?

They both seem relaiable but is one better than the other? semi-auto only.

[AR15barrels]

Mid-length is a MUCH better choice for a 16" barrel.

[SykoFreak]

I can't see any reason to go with a carbine gas system on a 16" barrel. I suppose you save a bit of weight from smaller handguards. With a mid-length gas system, you can properly mount a bayonet if you want to. Most importantly, the mid-length gas system puts far less stress on the internals which results in greater reliabilty. This thread has some info as to why
https://www.m4carbine.net/showthread.php?t=94