Well I screwed up

Tapping them probably won't help because the threads are junk (or did it just bugger up the entrance thread).Brownells has everything you need.If a tapping will clean up what you have,they have that and new bushings.If the threads are screwed(no pun intended),they also have a set with an oversized tap with corresponding bushings that will still use the original screws.Here's a little advice though.First get the special bit or driver that fits the bushing,a flatblade sucks and will really piss you off one day-ooooh,big scratch!The second is don't bother crimping the new bushings in if you even remotely think you'll remove them at some time.Clean the threads with brake cleaner,put a coat of BLUE Locktite on the bushing to evenly cover all the threads (just filling in the 'v'in the threads,not goobered up)and screw them in tight but don't crank down on them like they're gonna rattle out.This should fix you up.Oh,the gripscrews don't need to be as tight as everyone does them-that's what caused your prob.Snug is fine,but check them occasionally to make sure they're tight enough.