Im looking at throwing a .308 together for next years hunting season. I want to run a collapsible stock, would a rifle length gas work with a carbine buffer tube/carbine .308 buffer and spring? Or would a mid length gas system with an adjustable gas block work better? Ive looked around and have got mixed answers.

I have a rifle gas creedmoor with a magpul UBR (carbine buffer tube).

You need a heavy carbine buffer, heavier than the ar15 buffer.  I think mine's 5.7oz and I use an adjustable gas block + Tubbs flatwire spring.  I want the bolt to remain locked as long as possible and still function correctly.

I have a mid length gas with carbine buffer (DPMS .308 carbine & buffer spring.) To avoid issues I just went with an SLR adjustable gas block so I could tune as necessary. I’ve adjusted it once and left it as is, it’s been reliable.

Thats probably what ill do, thanks

In the AR-10 / .308 AR, the Carbine stock types use one of two different methods.

(A) is a standard AR-15 tube with a Shorter Buffer.  Toughter to tune because of the need for the special "shortie: buffers

(B) a slightly longer AR-15 styled type (not an actual AR-15 tube due to the longer length) using a Standard length AR-15 "H" buffer.   You can switch out standard weight, H2 or H3 AR-15 carbine buffers as needed to tune your rifle.

Important - don't mix parts between system (A) & system (B)

BIGGER_HAMMER