Felt recoil is a factor of:
- the weight of shot in the shell
- the amount of powder in the shell (dram eq. or velocity)
vs.
- the weight of the gun.
Other than load your own shells, there's not much you can do about finding shells with less buckshot or less powder. But, you have full control over the weight of the gun.
Take the recoil pad or butt plate off. Assuming the butt stock is held in place by a thru-bolt, there'll be a large cavity where the bolt goes in. Stuff that cavity full of lead and replace the butt pad.
The gun will become off balance, with the center of gravity moved well back of where it would normally be, but that difference will have a negligible effect on shooting performance compared with the flinch she must have developed by now. If the balance becomes an issue, add your weight more evenly between the fore stock and butt stock instead of having it all in the back (easier said than done).
You can reduce felt recoil more in this way than you ever will with light loads.
Pay heed to what others have posted above as well. When youngsters, ladies, or diminutive men get banged up by a shot gun, their first instinct is to hold the gun away from the shoulder. This is the WORST thing they could possibly do. Make sure the bruises from the last trip are well healed before trying again. Next time, make sure they hold the gun extra tight into the shoulder (not out toward their arm, either).
Between the extra weight of the gun and a proper mount, she'll see about a 20% reduction in felt recoil.
By all means, use the lightest loads you can find, but the real key is the weight of the gun. It's a common mistake to buy 20 ga guns for youth and women, thinking that they will 'kick' less. The truth is that a big, heavy 12 ga with light loads would deliver less recoil. ANY gun, regardless of gauge, will kick like a mule if too light for the load.
