Shouldn't need a piston on a rifle. In fact it could cause issues over time. The piston disconnects the can from the pistol barrel and adds energy to it so that the slide is forced back. That isn't needed in a rifle where the barrel is stationary. It could also negatively affect the threads. Try direct threading the can to a rifle barrel or use a 3 lug QC or other proprietary QC.
Yes, I know folks locally who use pistons where they aren't needed and I try to convince them. I have no idea if my convincing works or not. But research it yourself.
FWIW, the Surefire can that I wrote about above used a timed Surefire QC adapter.