CAM OVER

[Webster]

Why do guys recommend cam over when sizing brass. You cannot push the case any farther into the die than the shell holder touching the bottom of the die. Seems to me it's just a linkage movement and nothing to do with sizing.

 

[Ccrider]

Not true. There is a place when camping over where the case is pushed further in than if meeting the caseholder flush, at least on some presses.

 

[Straightshooter1]

I use a co-ax and my theory to cam over is for getting consistent pressure for consistent results on the brass, which I feel helps with getting the shoulder bumps I'm after. The more pressure one exerts there are changes occurring accordingly, as small as they might be, even when up against against a shell holder.

 

[Webster]

I use a co-ax and my theory to cam over if for getting consistent pressure for consistent results on the brass, which I feel helps with getting the shoulder bumps I'm after. The more pressure one exerts there are changes occurring accordingly, as small as they might be, even when up against against a shell holder.

None of this makes sense to me. You cannot push on the case beyond the shell holder touching the die. Are you trying to say the steel is getting compressed?

 

[PatMiles]

None of this makes sense to me. You cannot push on the case beyond the shell holder touching the die. Are you trying to say the steel is getting compressed?

In the case of a Co-ax the plates holding the brass flex.

 

[Ccrider]

What @PatMiles said. They flex in the sweet spot and allow for movement and cam over.
Start at a solid contact with your die and the press. Slowly adjust your die back. You will see what we are talking about.

 

[AckleymanII]

Webster, if you do not want to accept cam over, then get the Redding comp shell holders or grind .003 off the top of a shell holder and set your sizing accordingly.

 

[Straightshooter1]

None of this makes sense to me. You cannot push on the case beyond the shell holder touching the die. Are you trying to say the steel is getting compressed?

Yes . . . compressed and/or flexing.

 

[dolek]

Why do guys recommend cam over when sizing brass. You cannot push the case any farther into the die than the shell holder touching the bottom of the die. Seems to me it's just a linkage movement and nothing to do with sizing.

If you are reloading you must have a way to measure shoulder bump ? Easy to test... don't cam and then cam ...you will become a believer.

 

[JFrank]

@Webster From my prospective Shell holders have absolutely nothing to do with cam over.
Presses have different types of linkage, some have a flat spot at the top of the cycle others do not, the only one I know of with a true cam over is Harrell’s.
All that other stuff is just stessing the linkage to compensate for a ill fitting die.
J

 

[Daddymac]

http://www.mssblog.com/2016/04/14/cam-over-dont-do-it-just-dont/
If the link doesn't work you can copy and paste.

Not intentionally trying to stir the pot, because I'm a cam over guy, but Glen Zediker does come with a fair list of credentials when it comes to loading and shooting.

I may have to rethink and do some testing myself.

 

[Ccrider]

@SPJ are you saying ill fitting die to press or ill fitting die to brass/chamber. I agree with the former.

 

[JFrank]

@SPJ are you saying ill fitting die to press or ill fitting die to brass/chamber. I agree with the former.

Well it would be the chamber/die leaving the reloader to struggle with enough sizing therefore stressing the linkage for that extra .001-002 .

Once steel makes full contact with steel it can go no further.

 

[BoydAllen]

Years ago, I set a FL die so that it touched the shell holder with the ram at the top of its stroke. The press was a Rock Chucker. Then I sized a case, and with the case in the die, at the top of the stroke, there was a gap, that I measured with a feeler gauge. It was .006. Evidently the sizing load had stretched the linkage a bit. This is just another example of something being a bit more complex that it might seem to be at first glance.

 

[dolek]

Years ago, I set a FL die so that it touched the shell holder with the ram at the top of its stroke. The press was a Rock Chucker. Then I sized a case, and with the case in the die, at the top of the stroke, there was a gap, that I measured with a feeler gauge. It was .006. Evidently the sizing load had stretched the linkage a bit. This is just another example of something being a bit more complex that it might seem to be at first glance.

Agreed 100% ...way more to it . Sitting behind a keyboard is not actual experience.

 

[biggun2869]

I agree with Boyd, I feel camming over is more consistent. Mainly as he stated because of the press. Every case is NOT the same so you get a different reaction from the press. Many years ago P.S. magazine did a test on a whole lot of presses and they all deflected. Some of course more than others.
I use old wrinkle painted rockchuckers. (I have 2) witch didn't fare the best in the test but was at the top of the heap. Gary

 

[mensajd]

At a minimum, it takes out the slack from the linkages, etc. I measured a bunch of brass using a comparator both pre and post sizing and the cam-over process (with redding comp shellholders) yields very uniform results.

 

[NorCalMikie]

I feel camming over is more consistent.

Same same every time.

 

[Ccrider]

Every press is different. Some differences are caused by the design of the press including but not necessarily limited to just linkage.
The way that the jaws come together on my Forrester, if adjusted for full contact with the jaws of the caseholder the outside edge of the case flushes up with the flat surface of the jaws and that stops the case from gong any further into the die. As I back the die off, the edge of the case will at some point make contact with the beveled part of the jaws forcing them to move out and allowing flex, camover and more sizing.

 

[dgeesaman]

None of this makes sense to me. You cannot push on the case beyond the shell holder touching the die. Are you trying to say the steel is getting compressed?

If the press bumps the base of the die, your shoulder bump is not being set (with standard dies and shellholders.)

once I get my shoulder bump adjusted, the shell holder never quite touches the die. The cam over point is the spot where full sizing occurs.

It does make me think: if pausing for a few seconds seems to make sizing more consistent, then shouldn’t I be pausing at the cam-over point? Hm, things to think about during quarantine.

David