Whether you use your Barnett Quad 400 crossbow for hunting or target shooting (or both), at some point, you will need to replace the crossbow string. The Quad 400 is a compound bow that contracts by using a system of cams (the wheels mounted on either side of the bow's arc). This type of crossbow differs from a recurve model, and as such, requires a crossbow press (also called a crossbow clamp) in order to change the string.
Items you will need
Barnett Quad 400 Crossbow
Replacement string
Crossbow press
Empty your crossbow. You do not want to change the string with a bolt loaded into the crossbow's groove, as an accidental discharge could result in serious injury.
Place the crossbow into the crossbow press. Hold the bow upside down, so that the "business end" (where the arrow fires out) of the crossbow faces toward the ground. The unstretched bow and string should look like a smile.
Clamp the arms into the press. You can start with either arm of the crossbow. First attach one of the arms into the clamp on one side, then repeat by clamping in the other arm.
Crank the press to compress the bow. Turn the handle on the crossbow press until the crossbow string achieves a slackness sufficient enough to remove it.
Keep the old string in place and insert a new crossbow string along the same path as the old one. Double-check to make sure that you have laced the string through both cams in the same pattern as the old string.
Remove the old crossbow string.
Uncrank the crossbow press slowly then remove your bow.