This is a Mare's Leg type pistol made from a Ruger Charger with a cut-down 10/22 stock.
I liked the idea of a Henry's .22 Mare's Leg, but thought it would be more fun if it was a semi-auto. It is most effective to get a cheek weld on the stubby stock, push forward with the support hand, and pull back with the shooting hand for steadiness. Using this technique, I shoot almost as well as I do with a rifle.
For the legality minded, I sent the stock to BATF and asked if it would still be a pistol with a Charger action installed there-in. I have a letter from them saying it is, indeed, a pistol and I keep a copy in the case with the gun. This is not a short barreled rifle.