I have read that when you field strip a glock you are supposed to rack the slide back three or four times and let it go each time but I have also heard that this can be bad for the gun, does anyone have any input on this?
Old thread, but, it's still worth a comment: Why in the world would you do a stupid thing like that? Do you slam the brakes on in your new car in order to see if the ABS is working? If you bought a new hammer would you pound rocks with it just because it can take it?
Contrary to the, 'Glock Mystique', do NOT allow the slide to slam forward on an empty chamber - Ever! The breech face isn't made of some miraculous Austrian, 'mystery medal'; neither is the breech face all that thick; and, yes, I've seen a few that have shown stress cracks around the FP hole - It can (and does) happen!
Doesn't anyone read the Glock Owner's Manual? First you remove the magazine from the pistol; and, then, you should remove it as well as any other magazines or live ammunition far far away from the work area.
Do not - ever - return a magazine to a weapon you have just cleared UNLESS you intend to immediately return that weapon to service.
Glock recommends racking the slide exactly once; however, as a firearms trainer, I can tell you that it's always a much better idea to hand cycle the slide on a semiautomatic pistol TWICE before locking it, back, to the rear on the second cycle.
Next you're supposed to make a visual AND tactile inspection of the pistol's chamber in order to make sure that it's empty. Now, comes the tricky part: SIMPLY CLOSE THE PISTOL'S SLIDE BY GUIDING IT FORWARD WITH YOUR HAND - GENTLY!
Then, point the muzzle in a completely safe direction, and pull the trigger. Next, on a Glock, retract the slide about 1/8", pull down on the slide lock, and remove the slide from the frame. That's it - No pain, no pounding, no trauma, and no slamming the breech face into the barrel hood every time you disassemble your pistol.
If you haven't got an owner's manual give Glock a call. They're free for the asking; and, while you're on the phone, ask the tech rep. to research your pistol's serial number for any possible factory-related service issues.