what does cam over the press mean??

Normal setup of a sizing die is to screw die in far enough to just contact the shell holder. Screwing down to that point and then another 1/8 (or so) turn results in "cam over" and sizes the case a tad smaller than standard setting.

This is often necessary with the WSSM cases due to the greater case wall thickness and springback of cases after sizing.

Regards,
hm
 
Cam over on full length sizing is required on many guns, especially customs with minimimal headspace.

When you set your die in the press, be sure to do it while sizing brass. When you screw down the die to touch the shell holder, then size a piece of brass, you will find that the die is no longer touching the shell holder.
 
Cam over is when you set your die to touch the shell holder at the top of the press stroke, at contact if you apply a little more pressure to the handle it will give a little and top out. It feels like a compound bow when you reach the let off point.
 
It means the ram reached the top of its stroke, plus a little (over).
It's the same thing as PTDC on a piston, if you're familiar with measuring that.
 
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Originally Posted By: ackleymanCam over on full length sizing is required on many guns, especially customs with minimimal headspace.

When you set your die in the press, be sure to do it while sizing brass. When you screw down the die to touch the shell holder, then size a piece of brass, you will find that the die is no longer touching the shell holder.

Another term I've never heard of, but have been practicing. By trial an error, I found using this method for my T/C rifle barrel was the way to go. It cured my headspace issue.
 
When you have the die screwed down correctly, you will feel and hear kind of a thump-thump sound at the bottom of the handle stroke. Usually, camming over sets the shoulder back an additional .001-.002".
 
I don't know why anyone sets up a die like that. That's like saying all chambers are the same. The correct way to set up your sizing die is to measure a case fired in your rifle and measure the head space. You'll need a head space gage, I think Hornady makes them (my set was made by Stony Point). Now adjust the die so it sets the shoulder back about 0.002. I had a die that had to have the base ground down because it never would set the shoulder back far enough. Now you're not working your brass, but have clearance to chamber easily.
 


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