need info on how to bump casing shoulders back

[p5200]

I'm reloading for my Savage 10fp in .223. I am using a Forster Coax press with the Forster Benchrest die set. My loads with new brass chamber and bolt closes easier, than the rounds I used the FL sizing die on. What do I need to bump the shoulders back .001-.002"? or can the FL. sizing die be adjusted? I can close the bolt and I fired three rounds but it is tighter to close than on the new brass. Thanks for all help!

 

[abintx]

p5200 ...

I'm reloading for my Savage 10fp in .223. I am using a Forster Coax press with the Forster Benchrest die set. My loads with new brass chamber and bolt closes easier, than the rounds I used the FL sizing die on. What do I need to bump the shoulders back .001-.002"? or can the FL. sizing die be adjusted? I can close the bolt and I fired three rounds but it is tighter to close than on the new brass. Thanks for all help!

Unfortunately with the Forster CO-AX press you can't use a set of shims which would make adjustments easier. Unless someone knows something I don't. I've spoken with the folks at Forster and they have nothing on the drawing board which would allow shim use at this time.

With my CO-AX I place a reference mark [a black mark on a silver die and a silver mark on a black die] on the FL die in line with an edge of the Forster locking nut and then make 1/4 inch adjustments [measured on the top surface of the locking nut closest to the die threads] until I can seat a case in the chamber [with the firing pin removed from the bolt] so that the bolt "almost" closes by itself. So that I have to give it a "light helping hand" to close. You might have to use a 1/8" inch turn to hit your mark [.001" to .002"] dead on when you get close. I use a set of calipers of course and a device to hold the brass to take actual measurements during this process. Hope this helps with the CO-AX.

I may go back to my old RCBS Rock Chucker Supreme Single Stage Press and a set of shims but so far I'm getting what I want with the Forster.

 

[kansasvet]

It is also nice to have a way of measuring the case shoulder before and after sizing. As a general rule when you FL size, and your die is not adjusted down enough to set the shoulder where it belongs, the displaced brass at the base of the case pushes the shoulder of the case forward. In some cases you will not be able to close the bolt on the case because of this forward movement of the shoulder.
There are several measuring devices out there, I just happened to get started withe the RCBS Precision Mic. and like it. Measure five fired cases so you know where the shoulder is in the chamber and adjust you sizing die gradually till you bump the shoulder back .001 and you will be good to go. A word of caution, each time you make an adjustment to the die use a fired case that you have not used previously in your adjusting proceedure.
This is because the press "springs" differently for a hard to size case and one that has been sized previously.
Bad experience is a good teacher if it doesn't maim or kill you.