Terry Goode from Collectors in NH had a trench gun copy at one of the MA. gun shows a while back. $300 I think was the price. I was real close to buying it that day but never did. That gun has a bayonet lug on it and can't be sent into MA. for that reason by places that sell them. I never asked if and why the one Terry was selling was ok or not.
Damn lousy Massachusetts Assault Weapons Ban!
I gotta think if someone ran amuck with a trench gun copy, the last thing they'd be thinking was how many people the could skewer by attaching a bayonet to the friggin thing.
As for slugs and shotguns... try using them in a Mossberg 500 pistol grip Cruiser model. I can only do about 15 before it starts to get to me.