As far as a rebore, the inside of the chamber looked like it may have been bored, kinda wondered myself. But the shape of the barrel was'nt factory,it tapered off a little different and the crown was dished shaped instead of a recess with shoulders like a factory barrel, sorry for the lack of propper terminology ya'll. I should have paid more attention to the details, just looked it over on my way out. But I wondered if some one used a different reciever like you said Quikdtoo, ther aint no tellin who built it, I gotta run thru ther tomarrow, think I'll stop by and give it a good go'in over. as short as it is it would make a great truck gun for deer and coyote or carry on the 4 wheeler.