Yes ... and buy the extra spring kit if you want to be able to tune further than the gas block allows. I have a LWRCI REPR MKII 6.5 Creedmoor Elite, and I shoot suppressed. I was still over-gassed even on the lowest gas adjustment. The JP SCS Heavy AR10 with the heaviest spring has me ejecting perfectly at 3:30-4:00. It's expensive stuff, but on a $4,000 rifle, it's worth not scrimping. BTW ... for this to work, I had to order a 3rd heavy weight. It comes with two Tungstens and a Steel. I needed all three weights in heavy Tungsten, and the heaviest spring. Recommend calling them and special-ordering yours with 3 Tungsten weights, and the spring kit. Heaviest buffer, and tune with the springs. Make sense?