Odd resizing problem

[sbtennex]

First off, I'm not new at this by a long shot. Buddy of mine came over to load up a proven load of his on my equipment. He's living and working here, but waiting for his house to sell down south where all his reloading gear still is. His Ruger M77 has seen a lot of work, a .300 Win Mag. Using his fired brass, only one firing from new, I set the F/L die to just bump the shoulders, maybe .001 - .002 back. This meant positioning the die at about 1/2 turn out from touching the shellholder, typically what I do with my own .300. Tried to chamber the reformed case and it didn't fit. Working down the die position 1/16 of a turn at a time, we wound up having to set the die to not only touch the shellholder at the bottom of the stroke, but to continue down almost a half turn more to get the brass to chamber consistently in the same rifle. First thing was to clean it - bore and chamber. Didn't make any difference. Don't have a real good answer for this. It doesn't make sense. Almost new RCBS die set, clean and no wear. Any ideas???

 

[colinjw]

The only thing that I can think of is that your shell holder & his are his are slightly different enough to affect how far into your die the case goes.

A few years ago I picked up a lot of once fired .40's from a Glock for my P9 & had to grind the top of the shell holder down a bit to fully resize the case ( typical Glock fired case issue ).

 

[vagrantviking]

Where is the case binding in the chamber? Seem to be implying that its the shoulder not being set back far enough. Which is a bit odd to me. Maybe RCBS just ran the reamer a little too deep into the die body on that one.

Try a different set of dies and check that it isn't a different die dimension thats causing the trouble. IE body of the case not being squeezed enough. Do they make small base dies for the mags?