Thread: Case lengthening when bump sizing

Originally Posted by ebf

True shoulder bump sizing as it is used in benchrest and target reloading does not use a FL die (unless the neck portion has been reamed out, making it a body die).

What you are describing above (FL die screwed down only far enough to bump the shoulder) would still size a portion of the neck. Measure the neck OD or ID before and after sizing to confirm this.

True bump dies do not touch the neck at all. The diameter of the neck is the same after (shoulder and body) sizing.

My primary concern during reloading is to work the neck as little as possible. Neck tension is the holy grail w.r.t accuracy, and I do everything I can to get consistent neck tension.

What I do is this:
Body die to push the shoulder back (but not touch the neck)
Collet die to size the neck (in as concentric a way as possible)

Or you could combine both operations into one by using a bushing bump die with appropriate bushing to give you the neck tension you require.

Both these methods do not use an expander ball, so the neck is never stretched beyond the fired dimension.

You can avoid one of your steps by annealing and taking out your expander. Simple. Never had any issue with neck tension after proper annealing. There is plenty of nonsensical rubbish that you need a certain very expensive machine to properly anneal. Best you tell that manufacturer to read about the Houston boys. Without the expander and properly annealed brass your neck is sized correctly because it is squeezed during proper sizing.If your die is sizing the body of the brass it must logically be sizing the neck. Why they invented the expander now stumps me. The only logiacl explanation is that dies were designed before the effects of proper annealing of brass was understood. My 2C. Bullet seating is easily aided by chamfering the inside of the neck.