Ammo definitely does not have to be 40 grain bullet. I use -ONE- brand of ammo in my GSG 1911-22, and that is the Federal Champion, 36gr plated HP, bulk packed in either 375 or 525 count boxes. This is the stuff that is most often sold at Wal-Mart... or shall I say, it
used to be.
I bought this pistol in the late spring of 2012 and proceeded to put 3,900 rounds through it in six months time. All of it... Federal Champion 36gr plated HP.
I have only taken it out three times since November, went rimfire went scarce. My reasoning is simple-- I have many rimfire handguns and I love shooting them all. I really, really love to shoot the GSG also, but I'm running 14-round magazines and I have five of them so when this pistol shows up on a range day, 300-500 rounds is the norm, and I simply don't have access to that ammo like I once did. Of all the handguns I own, nothing
sucks more ammo from me than this one does in a single range session. So I had to quit shooting it, pretty much.
4,616 through this pistol to date. It'll be two years old in May of 2014, which is when the warranty expires. My original plan was to see if it would shoot to destruction in that amount of time, but I can't get the rimfire ammo anymore.