I had a buddy with an old Cooey single shot 20gauge. He wanted to cut it down and balance it so his 13 year old son could better hold and shoot it. He took a couple inches off the barrel (still legal length)and an inch or so off the stock. Added a new front bead and sanded , clear coated the entire thing, added a strap and mounts and a hammer extender. Very nice to look at when he was done considering that this thing sat in a garage for 30+ years and had a light surface of rust through out.
It indeed looked very nice to look at, but having cut off the full choke ( now true cylinder) it had no range and would scatter pellets at anything past 30 feet. It was ok for shooting grouse at close range, but that was about all. I think he would have been better off to leave the gun the way it was and wait one more year until the boy was a bit bigger and could handle it better. That old 20G would have held a nice group our to 75 feet or better before it was modified.
I've had this old shotgun for a over dozen years now. It was left behind when he moved away and I've had to register it because it was in my possession. Like I say, Looks nice, but has little practical use other than a trainer for a youth or small person.