Stupid 17/223 upper questions.

[big_matt_duq]

Forgive me ignorance in regard to the ar platform, I'm a bolt gun guy. I have a Noveske afghan with a Magpul ubr on it so I'm assuming all the buffer parts are carbine and gas length is mid. Is this correct? I want to build a 17/223 upper with a black hole barrel. What gas length would be best to go with? I was thinking rifle so it would be the softest shooting but if I have to swap buffers I will just go with something else. Also would an adjustable gas block relieve the issue like I think it would? I plan on running it with my harvester 30 until I buy a 223 suppressor so I figured the adjustable gas block would kill two birds with one stone. Anything else I haven't thought of?
thanks,
matt

 

[TonyTheTiger]

Buffer system length gas nothing to do with gas system length. Generally the longer the gas system the better off you will be but how long is dependent on barrel length.

 

[big_matt_duq]

Barrel will be 20 or 22 inches. Can't decide.

 

[TonyTheTiger]

For any of the cartridges I'm familiar with I'd say rifle length gas for sure, but I don't know anything about the 17's or if they have any unusual dwell time or pressure issues. Try asking the guys on the BHW forum.