Grinding die to reduce cam over???

[Webster]

I do prefer slight cam over, to take up any slack in the linkage. I don't think it's any straighter, but bump is more consistent, ime. Lots of people remove some material without any problems so both ways apparently work fine. Not all presses cam over either..fwiw.

Never understood cam over. The die bottoms out on the top of the shell holder. You cannot push the case any farther into the die? All your doing is forcing the linkage over the center of rotation.

 

[swd]

Never understood cam over. The die bottoms out on the top of the shell holder. You cannot push the case any farther into the die? All your doing is forcing the linkage over the center of rotation.

Not all dies should bottom out on the shell holder. Unless you check, that can result in too much headspace or there are probably more than dies guy’s realize that are too long and don’t set the shoulder back at all. Dies are a hell of lot less precise than people think.

 

[6MMsteve]

removing material from the bottom of a conventional sizing die should not be an issue, it already has a mega chamfer on the bottom that does nothing the chamfer is at .050 or more all dies have this, I see no issues removing .020 from the bottom to get the sized brass u want....I done my first one a week ago after breaking 2 shellholders and it worked perfect...it will be my preferred way from now on

 

[AlNyhus]

If the shell holder or die are ground even a little uneven, would that make bumperover cattywampus? Effecting brass straightness.

Yes...you want the face off (shell holder or die) to be as square as reasonably possible. A little cam over is beneficial for loading the press consistently.

 

[bulaman]

Anyone ever grind a die to reduce cam over? My current 284 barrel requires a pretty significant cam over to get a .001 shoulder bump. In fact I’ve ruined my little cover plate on my co-ax. I thought I would be smart and flip the plate over, but within 10-15 cases I created a new indention and this one has a little cant to it. I’m concerned I may be introducing some runout in my final rounds. I’ve got a new one coming but need to get this figured out for the immediate future. This barrel is nearing the end and I’ve got a different reamer for the next one.

I’ve considered grinding the bottom of the die, which I’ve done on a cheaper 25-05 RCBS die. However, this is a Redding shoulder die and I’m sure if I screw it up they will be on a 6 month back order.

I’m thinking I’ve either got to grind it square or grind it enough to prevent cam over. Thoughts?

I've removed some off of many dies and it has eliminated the exact problem that you are having and hasn't, for me at least, created any other problems.