Full-Length Sizing

Full-length sizing runs the whole case into a die that squeezes the body, shoulder, and neck back down after firing has expanded them to fit the chamber. The result is a case that chambers smoothly and reliably, which matters for repeaters, gas guns, and any rifle where easy bolt closing is non-negotiable. It is the default approach when ammunition must function across more than one rifle.

The key adjustment is how far the die sets the shoulder back, known as the shoulder bump, which controls headspace and how snugly the round fits. Properly set reloading dies bump the shoulder only a couple thousandths so the brass is not overworked and case life stays reasonable. Shooters who load for a single bolt gun sometimes prefer neck sizing instead, trading universal fit for a tighter chamber match.