Neck bumping

[Jrji]

I've decided to bump the neck on fire formed 6.5 CM brass, wondering how many thousands of an inch to start with?

 

[MartyK2500]

Do you mean bumping the shoulders?
I measured headspace from a fired casing, and give it a 2 thou bump for a target bolt rifle.
Using a redding body die

 

[CyaN1de]

Have you got a comparator capable of measuring to the datum on the shoulder?

If so, then .002-.003 push back from the fired case measurement is adequate for bolt guns.

If not, then you need to get one before you start bumping shoulders.

 

[stubblejumper]

I you are talking neck tension, I go for .0015" to .002" neck tension. If you are talking bumping the shoulder back, bump just enough for the case to chamber without resistance.