Its her grip!
My son and I took his girl friend to the range yesterday. I have a G19 and G34 and my son has a CZ75B. She found the slide easier to rack on the Glocks so she shot that first. Multiple fails to feed and stove pipes with either Glock with several types of ammo. I shoot that Glocks and they work great. As near as I can tell, she has a solid "IPSC Grip" on the guns. But they just won't run for her. She was also 4 in low at 12 yards, which I attribute to flinching. We give her my son's CZ and she's on target and it run great.
Am I missing something? What could be wrong with the grip that I can work to correct for her? She's a grown up who works out regularly. She is bigger and stronger than the grandmother I saw shooting a Glock at a recent USPSA match I shot. I can't believe it's a strength thing.
Its her grip!
She could have a solid grip on the gun, but if her wrist and elbow isn't locked, she'll have issues.
They worked for you, so it's definitely her.
Yeah, I agree with paratrooper. I, also, think that she's either breaking her (momentarily unlocked) wrist; AND she might, also, be holding a Glock off-center with the heel of her gun hand. (Whenever this girl grips a Glock, the muzzle and frame have to form a straight line with the heal of her hand.) IF she's got, 'too much thumb' against the back of the frame then the problem you're complaining about could occur.
Ideally, the wrist should lock, the elbow should lock, and you manage recoil by, 'shooting a pistol off your shoulder'. In effect the entire gun arm becomes an invisible rifle stock. I've been teaching these things for many many years. In my opinion what you're really saying is that your son's girlfriend hasn't, yet, learned how to correctly MANAGE A PISTOL'S BACKSTRAP.
Neither do I believe, on the basis of what's already been said, that, 'She's strong.' Glock pistols have a very weak and very loose modified tilting Browning lockup. CZ, on the other hand, has a tilting Browning lockup with a much tighter set of lugs. (More like the Browning P-35, 'Hi-Power'.) Of course Glock slides are going to be easier for a person with only modest hand strength to pull back and operate. This very feature is, also, going to make a Glock pistol more difficult for this girl to operate without experiencing all of the problems you describe.
(Don't try to, 'see' limp-wristing'. Many times it can be invisible; and at other times you might be able to spot it by a problem shooter's excessive muzzle rise as the pistol discharges. The strongest proof for limp-wristing is frequent failures-to-feed when an otherwise properly functioning pistol is in the hands of only a single shooter.)