The Diablo Upper is Primary Weapons Systems’ answer to the 7” AR-15/M-16 series upper.  Rather than simply bolting on an existing product and calling it revolutionary, PWS stepped back and designed a system from the ground up to work specifically with the extreme pressures of the 7” barrels.

 

We started with the barrel and after careful research decided on a 7” (not 7.5”) stainless steel polygonal bore barrel with a 1:8 twist.  A match bolt carrier assembly is housed inside of a MUR-1 (mil-spec) upper receiver with a billet machined charging handle.  Low profile quad rails give the most possible room for accessories and XTM rail covers from Magpul are included for when the picatinny rails are not in use.

 

The Diablo upper utilizes a long stroke piston system for additional dwell time and smooth recoil.  The system is rounded out with the new CQB comp from PWS - a comp designed for short barrels that compensates, suppresses flash and directs all the blast forward.