That takes me back...we had that exact fireplace when I was a kid. (5-10)
Man, I've seen guys pull high scores with a mossberg 500 and a buttstock with a pistol grip. Shoot the shot outta that 390 and when the gun becomes your limitation....then worry about that BS. You will eventually hear it from some shotgun snob that rolls in with a $12k beretta (or worse) and you can laugh the whole way home when you outshoot him, or land within a couple of him. Had just as much fun for 11.5k less.