"The K9 12.5 offers a proprietary patrol length gas system that is smoother than carbine length, more reliable than mid-length. Features an optimized gas port to run reliably suppressed and/or unsuppressed. The K9 continuous taper is the most effective profile to dissipate heat from hard use. With weight shifted to the back of the barrel, modern attachments on the front of the rifle create a perfectly balanced and better handling rifle. Updated target crown carried over from the Purebred series. Features no 90 degree cuts, improved harmonics, fit and finish. NOTE: COMES WITH PATROL LENGTH GAS TUBE"