I just bought a new glock 21 45 acp and i shot a few rounds through it and it jammed, once i got home and cleaned it i noticed that the recoil spring slipped off the barrel where it should be setting in the half moon shape of the barrel.Anybody else had this problem.

Here's a hot new flash for ya! The recoil guide rod assembly (includes the spring) is not supposed to sit in that half moon ASSEMBLY NOTCH when the slide and frame are together.
You need TO VERIFY that new pistol AND yourself as well. There's nothing wrong with your new polymer frame Glock that running three or four hundred rounds through it won't cure.
Last report I heard: Illinois State Police = 750 rounds fired before a Glock is released from the armory for field service. My Glocks? 500 rounds each before I carried either one of them. You've got some shooting to do!
PS: OK, if it's just a range gun then it doesn't matter. This said: It's a good idea to stay away from tungsten rods because, sometimes, they cause binding; and, the standard factory spring weight for the G-21 is 17#'s. A 13# recoil spring will certainly reduce perceived recoil; however, if your loads aren't designed to match that light weight spring, you may also start to get FTF's.
