Camming Over, the Real Story....

[Shane Tuttle]

I've done some searching on the issue of "camming over" your press.

I have the Hornady Lock 'N' Load AP. I also bought the New Dimension Custon Grade Dies and the Taper Crimp Die. In the instructions, they specifically state to raise the ram to its highest position without camming over and then thread the die into the press until the base touches the shell holder head.

I've never really seen a problem with my loads by using the "mechanical stop" of the press and then screwing the dies down. My logic was that the stop wouldn't change and it would keep from applying stress to the dies and shell holder.

Here's a link that started the discussion, but never really gave specific reasons:

http://www.thefiringline.com/forums/...t=over+camming

Am I doing this wrong? The Lock 'N' Load is used only for pistol cartridges. However, I have a RockChucker Supreme single stage press for rifle cartridges. For rifle, I try to be as precise as I can due to target shooting.

What are your thoughts, methods, links for good info?

[jamaica]

I always set my dies so there is a cam over when crimping, and belling pistol cases. The reason I do that is because when the press cams over, that is as high as it can possibly go. Since there is no stop to set on my press, that is how I can tell how high it is going and every casing will be treated the same.

One other operation I use a cam over for is if I want to just neck size with a full length sizing die. I set the die so there is a small gap between the shell holder and the die and the press will cam over then.

All that cam over means to me is that the ram is topping out. If there is any other importance to the phrase "cam over" I am not aware of it.

The ram will actually come down a bit after cam over, and I think they are trying to tell you to adjust when it is at the top. When I full lentth size, I set the die deep enough that the press doesn't cam over and the shell holder hitting the die stops the motion. This then is full length sizing because you can't press the casing in any further than that.

Have a great day!

[FrankenMauser]

I rarelly full length size. That is the only time I set dies up the way a manufacturer reccommends. (Usually I still tweak it a bit. Manufacturers' tolerances can get you in trouble.)

For any other operation on rifle or pistol cartridges; neck sizing, bullet seating, belling, etcetera; I set the die however I need, while letting the press cam over. This way every stroke is the same.

But, I also have a Rock Chucker. It cams over at maximum up-stroke, and doesn't fall.

[jmorris]

I set my size dies up using case gauges once the casing is sized enough to check out in the gauge I lock the die in place. This method seems to give me maximum case life with rounds that will feed through anything.

[F. Guffey]

TuttleB, the instructions call for an additional 1/2 turn after the shell holder contacts the bottom of the die, that is .071 + thousands, with out a case in the shell holder, the .071 thousands is not cam over, it is strain and crush that translates to binding the press. I do not have a case that requires that much crush, again I control sizing with a feeler gage, the strain and or crush I feel when sizing a case is controlled, the gap between the shell holder and bottom of the die controls the maximum amount the case can be sized, I have 'springy presses' that are better suited for seating bullets.

The Rock Chucker by RCBS will not cam over with out a shell holder and die, grinding the right link and toggle will allow the press to cam over, as built, when the two pieces make contact, upward movement stops, if the travel up is hindered, the press is placed into a bind because the movement is restricted, again the press never reaches cam over.

For those that have a cam over press, the came over press sizes on the way up and again on the way down, after cam over.

F. Guffey

[F. Guffey]

a cam over press,

F. Guffey

[Shane Tuttle]

Thanks for y'all's input. I think we're in agreement here to a certain extent. When the handle of the press is down all the way, the ram is up at almost its highest position on my press. I think the ram comes back down maybe .001" or so. I think by setting my dies to touch the shellholder is a solid baseline where to go from there on settings.

Tuttle8, the instructions call for an additional 1/2 turn after the shell holder contacts the bottom of the die, that is .071 + thousands, with out a case in the shell holder, the .071 thousands is not cam over, it is strain and crush that translates to binding the press.

I know. This is where I see a problem putting a stress on the components by using it as the travel "stop". I'd rather use the press' stop lugs to tell me when to cycle back down rather than the components.

My point is that I see it in press instructions as well as other members here basically saying that "cam over" is a big "NO, NO". I'm trying to get further information as to the whys and therefores.

[wncchester]

Trying to set an FL die correctly by "touching the shell holder" or "turning the die 2.5 turns", concerns of cam-over or not, etc, is a mistake. Measure the head to shoulder lengths of the fired cases and adjust the sizer until the shoulders are being set back maybe 2-3 thousants, how ever you wish to do it. We can't be more precise than that because brass spring back is not precise enough to hold what we may size it to any better than that, period.

There are at least three tools on the market to do just that. I prefer the RCBS Precision Mik best but the Hornady and Sinclair tools and a dial caliper can do just as well.

Changing a die a full turn equals .071", not a half turn.

[F. Guffey]

wncchester, you are correct, 1/2 turn would be .035+ thousands.

When it comes to reloading there are no standards, we shoot ammo, not gages, if there were standards like the go-gage, we would remove the primer punch/neck sizer ball assembly from the die, install the die in the press with a shell holder, insert the go-gage, raise the ram, adjust the die down until it contacted the go-gage, after the die made contact with the gage, secure the lock nut, lower the ram and remove the gage then raise the ram, if there was a standard, the gap between the shell holder and bottom of the die would be .005, if the shell holder deck height has not been changed by grinding and or the bottom of the die has not been ground off by the misinformed.

I use a feeler gage to set up the die and make my gage for measuring case length from the head of the case to the shoulder.

Cam over is a term used when presses cammed over, now the press is crammed over, a term we used in the oil field when securing anything with a chain would be more appropriate today, we used a BINDER but mechanically the term binder does not sound as good as cam over, I suppose we should have said 'we cammed over the handle and put it into a bind'.

Herters' catalogs of the 60s had illustrations demonstrating deflection with gages on their presses when sizing a case, they did not test for deflection by adjusting the die down and putting the press into a bind, just how tough is a case to size with a good lube, how tough is it to size a case with a lube that is not effective at reducing resistance?

Spell check does not like 'cammed'.

F. Guffey

[Alleykat]

The Wilson case gage is a pretty inexpensive and simple method of setting up the sizing die for proper shoulder-bumping.

[F. Guffey]

Alleykat, the chamber in the rifle has been paid for, I purchased 850 30/06 cases, once fired, everyone of the cases will fit into a Wilson case gage, none of the cases will fit the chamber of any 30/06 chamber I have including a test gage I made with the reamer that cut the chambers, it is a matter of keeping up with two measurements at the same time, case length is an included measurement meaning the case is measured from the shoulder forward and from the shoulder back, again I have a M1917 Enfield that has .016 thousands head space, the .016 head space can be added to the length of the case from the shoulder to the head of the case but not from the shoulder forward, as stated, there is no 'standard' in reloading, I shoot ammo, not gages. After that it becomes a matter of determining head space in thousands, not go, no and beyond, then there is the matter of adjusting the die for sizing, get a feeler gage for $11.00 or fill the tool box with gages, without a standard and the absence of the term 'transfer' there will always be someone saying it can not be done and the only answer is purchase another tool.

F. Guffey

[wncchester]

I agree that the Wilson, et al, case gages only show the min and max SAMMI dimenstions of our cases or ammo. That does NOT tell us anything specific about how our ammo actually matches our chamber tho. We need a different tool, or gage, for that.

Call it what you will, a fired case is, in effect, a good "transfer gage" we can use to set our FL dies to closely make our ammo match our chamber If we can measure it. There are indeed various methods of stumbling through the sizing and seating process but good gages have been developed by some very intelligent people to make those measurements easier, and those tools - gages - work quite well.

I can't measure my fired cases, head to shoulder, with a feeler gage, but I can with the RCBS Mic, etc. When setting my FL sizer, I can also measure exactly what I'm doing to the case, head to shoulder, which I also cannot do with any type of feeler gage.

When seating, I can use the same Mic, etc, tools so I can seat bullets to a specific depth relitive to the origin of the lands. I cannot do that with any simple auto mechanic's feeler gage.

We all use the measurement tools we prefer, from nothing to elaborate, but our ammo can benefit we know what we are doing, step by step. That is best done with a gage of the proper type.

[F. Guffey]

"I cannot do that with any simple auto mechanic's feeler gage"

"but good gages have been developed by some very intelligent people to make those"

"I can't measure my fired cases, head to shoulder, with a feeler gage, but I can with the RCBS Mic, etc"

Not long ago there were answers being given to questions regarding die and shell holders, seem hand loaders never knew the versility of the reloading press, mindlessely the hand loader pumped out ammo like cutting cookies with a with a cookie cutter, then, right after that answers were given about HEAD SPACE, the answer was always GO, NO and BEYOND, take it to a gunsmith, set the barrel back etc.,

I make tools that check head space from a 'short chambere' .012 thousands under a SAMMI cartridge (.017 under a go-gage) to .020 over a SAMMI cartridge in .001 thousands,

I make a gage that measures the distance from the head of the case to the shoulder in .001 thousands, at some point here you should realize I am not the one STUMBLING, I do not perceive the feeler gage as lowely and unworthy nor do I confuse the automotive feeler gage with a machinest feeler gage.

Standard, the feeler gage IS a standard, I have two height gages that use a dial indicator + one Pratt and Whitney electronic gage, all total the three gages weigh 125+ pounds , with the exception of the electronic gage, I use a feeler gage to test accuracy.

I can measure the stretch of a fired case at least three ways, one includes the the Wislon case length gage.

Grinding a shell holder or purchasing the 5 shell holder set from readding that cost between $40.00 and $60.00 is not necessary, if the feeler gage is available and in the hand's of a skilled hand loader, the intergity of the shell holder remains. Grinding the base of the sizer die is mindless, anything accomplished by grinding can be accomplished bith a feeler gage (in .000 thousands) including using the standard sizer die as SMALL BASE die.

F. Guffey

[F. Guffey]

accomplished bith a feeler gage, a better choice of words would have been 'with' instead of 'bith'.

sorry about that,

F. Guffey

[j3a5a7]

Jamica u r 100 % correct. when setting the die u r told to go to the highest position on the ram. u then screw the die down to the point of touching the shell holder, then back it up a portion of a turn. Thus if u cam over u will be gone to the highest position of the ram and (u cam over) then u start to lower the ram even though the handle is still in the lowest path of its travel. If u then adjust the die to this setting the ram will not be at its highest position, thus when u try to raise the handle of the press u are subject to damage the die or shell holder if in fact u can even raise the handle. Thanks for making me think