Hey britz
It depends upon what die you are using. For example if you are using an RCBS full length die the instructions say to raise the ram with the shellholder installed, then thread the die in until it hits the shell holder, lower the ram and thread the die in an additional 1/4 turn. Those are the instructions for full length resizing which is essentially pushing the shoulder back far enough so it does not contact the chamber shoulder anymore. Most other dies will give instructions and they will all say to adjust the die somewhere in that area of hitting the shell holder.
What you really want to do is adjust your die so that you only push the shoulder back just a smidgen (define smidgen as .001" to .002") so that there is still a very little contact between the case shoulder and chamber shoulder but you have gotten rid of the "crush fit".
You need to get the rifle out and keep it handy to the resizing process and proceed as follows:
1. Raise the ram and thread the die in until it hits the shell holder.
2. Resize a case and chamber the case in the rifle paying attention to the amount of difficulty of chambering.
3. If the bolt is harder to close than closing it empty, then you have some crush fit
4. Thread the die in a very little bit. A very little bit will go a long ways in shoulder bumping.
5. After each resizing chamber the case in the rifle, you will reach a point where the bolt goes from hard to close to no resistance from the case. That is the point you are looking for.
You might want to thread in and out a very little amount until the bolt has just a slight resistance. That is Partial Full Length Resizing and will work your brass the least from firing and resizing.
A very handy tool is the Hornady Headspace Gauge
MidwayUSA - Hornady Lock-N-Load Headspace Gage 5 Bushing Set with Comparator . Mine is indispensable for measuring the shoulder bump just don't know why they charge so much. Probably just because they can.
