Ladies and Gents, I have a recently purchased PTR91 GI rifle that I am trying to remove the cocking tube end cap on to put my bayonet adaptor on. I have searched on here, MilitaryFirearms forums, and google yet haven't managed to come up w/ anything. I punch the release button on the side of the cap, but it doesn't budge. I have even used a pair of pliers for better grip and it doesn't budge. Has anyone seen this? Any help is greatly appreciated!! Happy Thanksgiving to all!