i was on the mossberg website and seen that they had a muzzzleloader conversion barrel for shotguns. i am thinking about buying it buti'm not sure if any one has used one or something like it be fore

I haven't heard anything good about it because i was thinking about doing the same thing.

My brother-in-law had one and it was very accurate. However he never cleans his muzzleloader untill the end of the season. He would site it in then not clean it. The breach plug ended up seizing up on him and the accuracy started to go down hill. He ended up getting rid of it.
Clean it after every use and it will last a long time.

how much is the conversion? I haveMB 500...Haven't used it in several years.....we'll since I bought a bow

I'm not trying to tell you not to buy Mossberg or any other brand of gun but usually a barrel will cost all most as much as a new gun. A lot of stores put muzzle loaders on clearance this time of year and you can get a real good buy.

If youre going to go with that barell you have to make sure youre using a 500 with 6 shot magazine. Also make sure that the barrell would be legal in your state as the mozzber muzzel loader barell is not legal in WI. Something to do with the breach.