She may feel OK with the longer stock, but that is probably a matter of her not knowing how it should fit. If the stock isn’t pulled tightly into the shoulder, the felt recoil will be worse. A shorter stock that fits her better will help her get it tight into her pocket and mitigate recoil. The shorter stock will also put the forend closer to her, making it easier to cycle. Additionally, the Hogue ShortStock has a thick, soft recoil pad that works very well.
I’ll admit, I’m making a lot of assumptions on my part because I don’t know your wife, her background, or how much she has trained with a shotgun.
Buy a Hogue ShortStock and have her try it. If it doesn’t make an improvement for her, I’ll buy it off you for what you paid for it.
Nothing wrong with a 20ga with the right load in it. Indoors, not having to reach out very far, I would have no issues trusting the right 20ga with the right ammo in it.
Another option is a gas-operated 12ga, or 20ga. With all things being equal, a gas-operated shotgun will have less recoil than a similarly sized/weighted pump shotgun.
Another thing to think about is the source/cause of malfunctions with shotguns. The majority of malfunctions that I see with pump shotguns is due to user error; short stroking or not pushing the forend back forward enough to lock. On autoloading shotguns of any type of system, the main causes of malfunctions are ammunition or lack of maintenance (dirty, dry, or dirty n’ dry). Under stress, someone that hasn’t spent a lot of time practicing will tend to run the semi-auto shotgun more reliably than the pump shotgun.
