It's just my own openion. I have been shooting for some time now and not the most experienced shooter here but over the years I have owned many handguns from a lot of companies. I'm now 59 and for some reason I always carry a glock. I now own a 17, 21, and 22. I have a trp springfield and I love the gun but when I leave the house I always carry a glock. Not to say bad things about any other gun at all but if I were a young man again I would start out with a Glock and and stay there. And no I don't work for Glock. I'm planning on buying a 20 in 2011. Could anyone let me know if I can buy a 20 slide for my 21 frame from Glock and would it work?