If I put an adjustable sight 5906 slide on a 5903 frame, should I worry about increased frame rail wear? Was thinking the slides have "mated" to thier original frames and trading them might wear everything out quicker.
I wouldn't worry about excessive wear unless you plan to put tens of thousands of rounds through it a year. The 5903 and 5906 share the same slide, it's only the frames that are different. I have a 5903 SSV and 4 5903's and you can change the slides around without any problem. At least that's my experience. -Ed.
