Just tried to install 419 hellfire brake on my new sig PRS .308 rifle. No matter what I do I can’t pop in the brake to lock it in. The videos make it look effortlessly. It seems to hand tighten down and the brake seems firm, but I haven’t tried to shoot a few rounds through it either. The only thing else to mention is when I installed the adapter I had just a little bit of bore thread still showing. Not sure this means anything, but I thought I should mention it. Thanks