204 Ruger cases won't fit even after FL sizing

[17cal Fan]

Had this problem years ago with a 243. It boiled down to one thing. Not enough case lube in the neck causing the expander ball to drag the shoulder datum line forward as the ball was drawn out of the case. Proved it to myself when I purchased a Digital Headspace Gauge from http://www.larrywillis.com/ Some of the best reloading money I ever spent. For over 20 years now I have used it to set my dies and verify that I am using enough lube on everything from 17 Hornet to 30-06. Simply set a fired case in the gauge, note the reading at the datum line and then size the case. Recheck with gauge. If the ball drags coming out of the case, I know what the gauge will have to say. It will read higher, meaning the shoulder pulled.

And no, you would not expect that much flex in the shoulder but it's there and visible on the gauge.

 

[searcher]

The competition shell holder set permits you to do incrementally LESS sizing. In the instructions that accompany the set, it states that "[t]he number stamped on top of the Redding Competition Shellholder indicates its increased shell seat depth [emphasis added] over this standard, and thus the amount it will decrease case to chamber headspace (through less shoulder bump)."

When I bought my set of Redding Competition shell holders, I had visions of being able to use a different shell holder as needed for a particular load to keep my shoulders at a determined height. When you get down to controlling your sizing in small detail - those shell holders, while they seem sensible, are a PITA, as brass sizes differently after a few firings in between annealing, etc. - so you can't rely on the shell holder you used two firings ago to end up with shoulders at the same height - so one ends up needing to make an adjustment anyway. Better to just turn the die (which I keep a little loose throughout a batch of sizing) as needed to keep the shoulders right were I want them. The O-ring under the die works really well.