Yes, the barrels are rifled.
you get them on the floor from wooden barrels or steel barrels. then you can switch by using the scroll or the keypad
If you mean MACHINE guns, the answer is yes.
no
No. The barrels are not rifled
TC is one
Some did, but not all.
No. They work on the Rossi Wizard, which is designed to have quick change barrels.
It could be a cooper- someone that makes wooden barrels. In firearms, a person or company that makes barrels for guns.
Within reasonable limits, a longer barrel lets the bullet get pushed by the gunpowder for a longer time, and it moves faster.
The barrels are all the same length but the guns are staggered to allow room for the ammunition chutes to feed the guns.
Try the gunbroker.com, or do a google search on the specific barrel you need. Mid West Guns also carries Browning Barrels.