We have a little 20 ga youth model semi-auto on brackets over the inside of the bedroom closet door. The size is due to the fact that Maggie is "youth-sized" and can handle the weapon. It should certainly do enough damage. I had considered a pistol grip, although in NJ putting a pistol grip on a semi shotty makes it an "evil" gun and you can go to jail for it. I'd thought about selling it and getting a pump so we could use the grip configuration.
After trying a pistol grip model a friend lent us we decided that the pistol grip forced us both to carry the gun in a certain way, where with a standard stock we felt more versatile. She likes to tuck the stock under her arm and carry at the midsection, I found that the pistol grip on a short stock was awkward, and so standard stock just works out better for us.