I put a pistol grip on my HD shotgun. It did not stay on there very long before I replaced the wood. The recoil of a shotgun begs for a shoulder to rest it on. I found that the trade in size was not worth the lack of ability to aim.
I have an old wichester ranger model 150 that has a cut pistol grip handle and the recoil is nothing. I can honestly shoot it one handed (not safe I know) and it dont kick hard. I had a 870 with a tactical pistol grip from Cabelas that feels like a true pistol and I loved it.
Shortening the barrel is a good mod. But have a gunsmith do it. and leave the stock as is.
The nation that will insist on drawing a broad line of demarcation between the fighting man and the thinking man is liable to find its fighting done by fools and its thinking done by cowards.
To have the barrel cut off and recrowned would cost more than the gun is worth. I would trade it or use it for a truck/barn gun. I would like to find a throw away pump like that to leave in my barn. Every time we get a chicken killing critter hanging around I end up killing it with one of the luckiest pistol shots I have ever seen. I couldn't duplicate the shot with a case of ammo.