Looking to get this 12.5” barrel for a 6.8 SPC build.: https://www.ar15performance.com/inc/sdetail/7500

They will do whatever port size I request. I plan on running cheap S&B and Prvi Partizan for plinking and Hornady SST 120 grain for defense. Suppressed reliability without an adjustible gas block is first priority, but ideally would cycle w/o can also.

What port size do you recommend to be sure of cycling with a can and at least have a shot of cycling the defense ammo without?

Also, what weight buffer with Vltor A5 tube? I use H3 & 4 with my 5.56 shorties.