I did an 18" cylinder bore 870 with a pistol grip, and learned several things, with birdshot, normal loads, like dove loads, it was like a .44 mag in a handgun, with buckshot, not reduced recoil as it was not available then, it would recoil hard enough that the forend would come out of your weak hand, and to hit, you needed to point it with your eyes over the barrel, just like with a long stock, it was easier to pump with your strong hand, and keep the weak hand attached to the forend, but after a couple of rounds, the receiver kept getting closer to the body, until it hit you in the nose. the super short setup has it's place, but not in the home, I think the car and with a fold out stock, and if you go the pistol grip, get the forward pistol grip too.