I actually see these barrels quite frequently on eBay. they go fairly cheap. just look for the mossberg 500 barrels. If it doesn't fit right then turn around and resell it on eBay again. There are also quite a few gunpart sights on the net.
as far as i know yes, i have seen both receiver ends of both barrels and they are almost identical
NoThis is from the Winchester Website:How versatile are the Model 1300 barrels? Will they fit earlier or different models?The Model 1300 barrels will fit Model 1200 receivers, but 1200 barrels will not fit a Model 1300. Model 1400 barrels will not interchange with Models 1200 or 1300 barrels.The Model 1300 Defender barrels will not interchange with the 1300 Field models and viceversa.
It appears that they are. You would be advised to have a gunsmith check the fit before taking it to the field or range.
yes
The number of barrels that can fit in a cylinder depends on the dimensions of the cylinder and the barrels. The formula to calculate the volume of a cylinder is πr^2h, where r is the radius of the base of the cylinder and h is the height. By dividing the volume of the cylinder by the volume of a barrel, you can determine how many barrels can fit inside.
No
The Montneel z1 has unique threading and has no after market barrels available.
Any Spyder threaded barrels.
No
yes
None