Ive got the design in my head it would have to be with a custom bolt but I plan on doing that any way. The thought of one over size case or jam due to dirt ect really bothers me. I have this happen in a few SA 22lr,s the round isint all the way in the barrel. no big deal on 22lr but it could be bad with a the much hotter x25. I suspose a looser chamber would be safer as far as bad ammo or dirt.