beebecl

Sounds like a standard Mossberg 500, like they still make. I remember they had a 'Regal' model 10-20 years ago. Like the Remington 870, the action is pretty much the same on all of the 500s, they just put them out in a variety of models with different furniture, sights, barrels, etc. Look up Mossberg's web site and I'll bet you can download the owner's manual for any model 500, which should show you how to take it apart and all. Most of the parts are probably the same as today's 500, and I'm pretty sure it would take any model 500 barrel.

Good luck.