Dye Ultralite Back

Q: Does it fit into a 2011 proto rail and what do you need for the front tip

A: Yes it does. You will need a Dye Ultralite tip: http://www.store.justpaintball.co.uk/barrels/dye

Q: What bore should I use for my BT-4 combat, or does it matter???

A: This barrel isn't compatible on your BT-4 combat. bore size is for serious player to adapt the diameter of the barrel to the diameter of the paintballs they are using.