Thread: Need help understanding shoulder bump

You can do it without measuring, but when it comes to reloading I measure everything...

The hornady "headspace gauge" has an insert for the caliber you use. I my case it is .400 for 308 family of brass. After firing, measure the shoulder to see what your fi reformed shoulder is. I then set up a Redding body die to reduce that by 0.002. Chamber the case to see that the bolt closes easily.

You might want to check your overall brass length as well. Difficulty chambering can be from multiple causes : brass needs to be trimmed, shoulder pushed back, or base is too tight for chamber (use small base die to fix this).

You can adjust the FL die to bump the shoulder, but unless you remove the expander ball, you are working the necks of your brass quite a bit. I am very careful with the necks of my brass, so use a body die, and then a collet neck die to reduce working the necks to a minimum.

You could bore out the neck part of a FL die, but dies are made to be incredibly hard, and are not kind on tooling, so you might struggle to find an engineering shop to do it.