Have you ever heard of bending an Upper receiver?

[LRRPF52]

I have heard of uppers bending doing something as simple as adding and taking off muzzle devices. BANG BANG!!

There should be zero torque applied to an upper when doing muzzle device work. The barrel should be clamped, and nothing else. I've seen a lot of people clamp the upper in a vice, then start torquing on their muzzle devices. We even had a forum member years ago torque their barrel out of the barrel extension.