I have never had a cap fall off yet, maybe cause I make my own nipplesthat fit tight on the caps.

I do the same . . . . machine a little groove on the outside of the nipple for the base of the cap to snap over. And then, of course, I had to make a little tool to get the nipple off if I didn't shoot it . . . . .

I also have a tool that I made out of an old spoon handle, cap remover on one end, flat screw driver on the other!