Is this cam over ?

[Bill Norris]

What we need to remember here is once the shell holder and die meet @ just touch there is still some play in the press. Screwing the die down to get cam-over will take this play out and probably will result in the brass moving another thousandth or two into the die which in my case did exactly what I needed.

 

[M-61]

The metal is moving in several places, actually - the die, the frame, the ram, and the links all deform ever so slightly to allow the ram to move.

If your're worried about the die being squeezed by this force, you can relax. The amount of force exerted by a press on the die is actually pretty small - not enough to compress the die meaningfully.

I’m not worried about the die being compressed any amount at all. I can’t imagine a hand operation press doing anything to the die. I consider the somewhat like a piston wrist pin. I’ve seen many horrific engine explosions including water ingestion. The wrist pins, though I won’t reuse them, seem fine.

 

[K22]

What we need to remember here is once the shell holder and die meet @ just touch there is still some play in the press. Screwing the die down to get cam-over will take this play out and probably will result in the brass moving another thousandth or two into the die which in my case did exactly what I needed.

This is absolutely correct!

 

[M-61]

Not the worst but the wrist pin was fine

 

[Rset]

We can debate this until hell freezes over but the bottom line is making whatever adjustment to the FL die that is necessary to obtain the desire amount of sizing.

Everything else and all the discussions previous to this are all the same. Agree or disagree, pysics are physics, force is force. Volume is volume in non compressible materials, and sizing is sizing. Call it what you want, but if you don't understand the process, all is irrelevant.

 

[Kracken McGraw]

What we need to remember here is once the shell holder and die meet @ just touch there is still some play in the press. Screwing the die down to get cam-over will take this play out and probably will result in the brass moving another thousandth or two into the die which in my case did exactly what I needed.

This has sure been my experience on the RC II ‘s.

 

[South Paw Sammy]

Posted about this before and noticed a few different people calling different things cam over and got a little confused. Ment to post a video then a few months back but never got around to it.
Anyhow finally fixed what I was talking about today. So what would you cont this as ? Cam over or something else?

That’s cam over no doubt

 

[DShortt]

Personally I don't care for the whole idea of 'cam over' or whatever you want to call it. I avoid presses that act in such a manner.

Obviously it's worked for a bunch of people for a long time and that's all well and good. I stay away myself. I like a press with a dead stop. Ain't moving that handle further than that unless you break a linkage part.

 

[6Creed73]

Personally I don't care for the whole idea of 'cam over' or whatever you want to call it. I avoid presses that act in such a manner.

Obviously it's worked for a bunch of people for a long time and that's all well and good. I stay away myself. I like a press with a dead stop. Ain't moving that handle further than that unless you break a linkage part.

Agreed, I much prefer a hard stop press. I get better consistency. Like you said, if the linkage hits a hard stop there is no issue with further movement beyond that point, no matter how hard you try.

 

[M-61]

Everything else and all the discussions previous to this are all the same. Agree or disagree, pysics are physics, force is force. Volume is volume in non compressible materials, and sizing is sizing. Call it what you want, but if you don't understand the process, all is irrelevant.

Wow. That cleared that up.
If you’re not confused, you don’t understand the problem.

 

[Zero333]

View attachment 1475116
Not the worst but the wrist pin was fine

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Not the straightest loaded round, Only the runout was a hair off.., but the bullet was fine



Couldn't help myself,.. it's a pic I found on the world wide web.

 

[Zero333]

The only time I ever had to cam over is when I wanted to use some 300winmag brass from a retired barrel to a new barrel. Otherwise I don't think I've ever had to cam over more than a couple of times just a tiny hair for semi-auto blasting using range brass.

That's why we use the Hornady case comparator. It tells us all we need to know to set up the die perfectly to bump the shoulder about 0.002"... I did an quick experiment with a few different cartridge brass and by fully caming over, the shoulders were pushed back up to 0.010". With that much headspace you're taking a risk of having case head separation after a couple of firings.

 

[Chubbs]

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Not the straightest loaded round, Only the runout was a hair off.., but the bullet was fine



Couldn't help myself,.. it's a pic I found on the world wide web.
View attachment 1475259

Runout or just chamber cut at an unusual angle.

 

[M-61]

=======================================

Not the straightest loaded round, Only the runout was a hair off.., but the bullet was fine



Couldn't help myself,.. it's a pic I found on the world wide web.
View attachment 1475259

Would like to see the die!!

 

[Shooter13]

View attachment 1475116
Not the worst but the wrist pin was fine

That is the new "cam over" rod! ;-)

 

[M-61]

That is the new "cam over" rod! ;-)

It always amazed me how the wrist pins seem to survive. And the vast majority that suffered engine ‘‘explosions’ were from what we called ‘taking the car for a swim’
In other words the driver chose to attempt going through a 4 foot deep puddle. I particularly liked when having the car towed in, was when they asked if I could fix by the end of the day!

 

[Doom]

Everything else and all the discussions previous to this are all the same. Agree or disagree, pysics are physics, force is force. Volume is volume in non compressible materials, and sizing is sizing. Call it what you want, but if you don't understand the process, all is irrelevant.

There is a misconception here. The die material, and any material is not really incompressible. As force is applied the materials does compress. In general it does not move by much but the reality is there is compression.

 

[SEM]

View attachment 1475267

Runout or just chamber cut at an unusual angle.

40 minute of angle chamber in conjunction with a 20 minute of angle scope base = 60 minutes. Never watch that waste of an hour.

 

[ronsatspokane]

Personally I don't care for the whole idea of 'cam over' or whatever you want to call it. I avoid presses that act in such a manner.

Obviously it's worked for a bunch of people for a long time and that's all well and good. I stay away myself. I like a press with a dead stop. Ain't moving that handle further than that unless you break a linkage part.

So when I started reloading some 50 years ago as a high school kid, there was essentially only one game in town and the major brand associated with that game required cam-over. So did the other brands as far as I recall. Few short of gunsmiths knew what the headspace was on their guns or what the optimum bump of the shoulder was. In my experience many dies are still cut to a length that requires cam-over. Now that I have all the gauges to measure every aspect of cartridge and chamber dimensions I see clearly what was unknown back then.

 

[Rset]

There is a misconception here. The die material, and any material is not really incompressible. As force is applied the materials does compress. In general it does not move by much but the reality is there is compression.

I agree with your premise, but not at the pressures our loading presses exert.