I have reloaded and shot thousands through my G27 and G22. No problems. I use jacketed or plated bullets only. Have had very good results with Berry's brand bullets. I chronograph my loads to confirm that are as close to factory as possible. All my brass is tumbled and inspected before it is reloaded and any brass that does not make the grade (nicked, bent, or looks suspect) gets discarded into the scrap pile. You can shoot lead bullets if you change out the stock barrel. Wolf makes aftermarket barrels that will fit Glocks and I have one in 9mm for my G22. So far I have been very happy with it.
Only two defining forces have ever offered to die for you:
...Jesus Christ and the American G.I.
One died for your sins; the other for your freedom.