Most of the above is absolutely correct. The barrel is easy to fit to the receiver as long as you have the set of barrel bushings you might need. It could be any one of about 6 different length bushings. That's like saying it's simple to fly on up to the cool ol' moon...all ya' gotta do is have a space ship. The kit, if you need it, cost around $200.00 these days {if you can find one for a 16ga.} Then there's the problem of possibly having to have the barrels chamber reamed to the chamber ring in the action. Yep...about one fourth of the chamber is a ring that screws into the receiver...the rest of the chamber is in the barrel so they are reamed together at the factory when the gun is made. The chances of having the new barrel flop right on and line up with that chamber ring in the receiver is right up there with Michael Moore ceasing to be an idiot. Again, it's all simple if you have the tooling. The reamer to align the chamber ring to the barrel is special, not just a chambering reamer because you have to turn it while in place with the gun together once the barrel is fitted to the receiver. That reamer is driven or turned by a bar thru the muzzle end of the gun...again not stuff the average gunsmith is going to have. Simply fitting the barrel assembly to your receiver is not hard and it will probably even cycle and chamber the shell but when fired it is almost certain to be stuck hard in the chamber and not extract until that chamber and ring get align reamed.