Now I'm not some moron who can't make decisions for himself, as I RARELY ask anyone for their opinion on anything. Though, I have been battling for a while on this decision and just can't make up my mind. SO, I can't decide, buy a KKM 10mm conversion barrel for my Glock 21, or buy a factory .45 threaded barrel for it and just buy a Glock 20 later?? I am going to invest in a suppressor this year for one of my guns BTW.... Thanks in advance for the help.