Failure to feed,the slide velocity is affecting the timing of the operation and failure to eject, the brass isn't leaving the pistol quick enough due to a slower slide which then on its return catches the brass..this is a service pistol,.not a tuned race gun so its feeding requires a solid grip for the pistol to function properly.
you have to provide a solid platform so the slide can,well....slide. All the recoil energy from the round is used to cycle the slide and feed another round
If the frame is allowed to move the slide and frame move as 1 unit the energy is used to move the whole pistol and there is not enough energy left when the slide starts moving on its own
try this,... take pistol in hand,.. holding frame firmly now (without ammo )go through the motions of load and make ready
using the same force to rack the slide.....repeat but this time loosen your wrist so the pistol kind of flops around should take more force to manipulate the slide...takes longer and requires more force...
it is also a timing thing,.. you have about 1/10th. of a second of recoil impulse to get this maneuver completed
make it harder, or take longer and your semi-auto becomes a hand operated firearm..
also check to see she is holding high enough up on the grip, higher on grip will help cycling as its a leverage thing...
Hope this helps
John
P.S. how does she handle the Beretta ? cocking the hammer first may make it easier for her to work the slide,and if the Beretta is more "forgiving" may be better for her to shoot, less malfunctions = more fun
My brother, back when he was 13 had these problems too we thought it was the pistol,..then Dad or I would run it and ..worked fine..he can still clear a malfunction faster than I can
+2 awsome advise