"Neck tension" query

by Hoot , Diversityville, Liberal-sota, Friday, December 18, 2015, 07:26 (3202 days ago)

Slightly off the beaten track (as usual)...

I am forming 9.3x57R cases from 9.3x72R parents. Everything goes along swimingly through the process until I seat a bullet. At this point, the dummy round will not chamber. I have traced this to the case neck being too thick.

My intent is to order a custom inside neck reamer but I am in a bit of quandary as to what diameter.

I will do a chamber cast (just as soon as the plumbing is done) to get the chamber's neck diameter.

So, two questions:
What clearance should I allow for the neck expansion in the chamber?
What interference in the neck (reamer diameter) should I assume for a cast bullet of a known diameter?

As always, thank you.