Thread: Case lengthening when bump sizing

Originally Posted by -BW-

Perhaps I have misunderstood the opening statements around the problem, but if a full length resized case won’t chamber as stated, then in my opinion it just hasn’t been sized enough. I’m not sure about the relationship between this problem statement and the following explanation about case lengthening?
If brass lengthens, as you explain, then it is longer at the neck, not longer at the shoulder where it contacts the chamber, so it would not inhibit chambering.
I believe there is more correlation than causation here and one does not effect the other.

I may have poorly explained this , as I said it's come up a few times of recent on the SD forum over here and opinion seems consistent on the cause. On occasion it has been the die being out of spec ' , perhaps the shellholder or just simply the die wound out and in need of adjustment.

I get where you're coming from , had I just f/l sized then I would expect the brass to move into the neck . At the time it didn't occur to me to measure case length to the neck , it would have been possibly of little use but more a point of interest.
This phenomena appears to occur at a point just before the case shoulder engages the die during sizing , which had the die been in contact would prevent the shoulder moving forward .

I can assure you that there is a point at which this occurs , I've measured it using digital calipers and a comparator to measure before and after and I always size 3 or 4 cases during set up first . None of the unsized brass I tried , were difficult to chamber.

It hasn't ever caused me a problem , I just use the appropriate shellholder or previously, just adjusted the die .

I'm sure this can't just occur in the UK .