Don't stress your press

[hounddawg]

I looked into the cast iron thing a bit more and am now of an opinion it is probably white cast iron not gray, gray does not make sense design wise. White is more flexible and stronger than gray. That hollow pin though is there for a reason and the only reason I can think of is to allow flex in the linkage to keep from over stressing the frame. That plus just the common sense of knowing there is play in the pivot joints so I would still bet a six pack of beverage that the play is in the linkage not the frame flexing

[Metal god]

I’ll add if you can say one tool is made by a chamber reamer which makes it legitimate . If another tool is made by the chamber it self by press fit agsinst the chamber walls with 60k psi or pressure, that tool should also be just as legitimate to measure headspace .

[hounddawg]

To me the test of ammo is what it does at the range. Today I shot a 96% 60 shot aggregate with some ammo that was only half developed, I am pretty darn sure none of the dropped points were due to how I set my case sizing or what I call setting the shoulder back. Cases were on 4th firing with no anneals since factory

[briandg]

When the shell holder meets the base of the die, that is it, that's the end, your case cannot be stuffed harder into the die than it already is, it has gone as far as it can, and camming over will do nothing but stretch or compress certain parts of your press by hundredths or thousandths of an inch.

Since the shell base itself is loose in the shell holder, your work is simply done when that shell holder presses up against the mouth of the die.

My press has a pin at the base that prevents cam over.

[BBarn]

As points of reference, I checked four presses for cam over. Neither a Rockchucker from the 1980s, a Rockchucker from about 2010, nor a Lee Classic Turret from about 2010 cammed over. A Hornady AP Press from about 2013 had a small amount (less than 0.002") of cam over.

Keep in mind that cam over of a press is a feature that is inherent (or lacking) in the press itself, and die adjustment has no bearing on whether a press cams over. That, of course, assumes the term is properly used.

The term can be misused to describe what happens when screwing a die down far enough, and raising the ram high enough, to place the press links and components in a bind such that a deep clunk sound is heard.

[David R]

Been following this from the beginning. I guess I don't understand. My press handle and linkage goes over center. This is how its made. I am sure of that. The die is screwed in so the case is sized properly. If its a carbide pistol die, its not supposed to touch the shell holder. I put the case in, the handle goes down and the ram goes up. The ram reaches its peak height then relaxes the last part of the handle stroke. The handle gets more difficult as the case is sized, then gets real easy at the very end of the stroke.

Over center. If this is what you are calling cam-over, its supposed to be there.


This is my only analogy. When compound bows came out they had cams or offset pulleys. The very first ones you pulled the string. It got harder until about 1/2 the draw length. Then it got easier. It was an over-center design.

The first ones had a stop at the end of the draw. This is how you knew it was at full draw. So you were pulling against a stop. You could pull as hard as you want with no additional change in the draw. This was counterproductive because the idea was to have an easy hold.

I feel once the press linkage has gone over center, its job is done, now return the handle.

Without the over-center design, you can apply a different amount of pressure on each round getting inconsistent results. Over-center assures the exact same ram stroke per handle stroke regardless of how hard you push on it especially once the stroke is complete.

How deep a rifle die is screwed in can make the over-center more difficult. A Point of diminishing returns is reached for the amount the shell is sized. Common sense should step in and if you have to lean on the handle to get it over center, then you are doing something wrong.

David

Sent from my SM-T900 using Tapatalk

[cw308]

Talk about a simple task ( reloading ) so confusing . Sizing brass I followed the instructions , knowing the basics , screwing the die down to the shellholder removing the slack between the threads , all made sense so far , removed all movement . What doesn't make sense to me it why go any further , this can't be good for the equipment . That's when I went with the Competition Shellholders , that made sense to me setting up the same way . Press isn't stressed , brass is softer and can be formed with the right tools . What's that saying " the path of least resistance " . Guys , I'm no rocket scientist like some . I don't care the make up of brass or the stress level of steel. All I want to do is size a case the size I want it and find the tools that will do it without over doing things that can cause wear and tare.

PS When I hammer a nail into wood the head stops flush with the board , I'm one of those guys.

[Jim Watson]

The top left arm pin is a hollow pin, I wonder if that is the weak link and designed to flex when x amount of stress is put on the frame to prevent it breaking.

I think that is so you can reach through the left pin with a long punch to drive out the right pin.

I once skimmed over the instructions for a Lee Collet Neck Size Die, screwed it WAY down in the Rockchucker, and blew the top plug right out of the die body as the linkage "cammed over." Lee replaced it but with a callout to their instructions not to cam.


The headspace on a .308 chamber is the distance from the bolt face to a .400" datum in the shoulder cone.
Well, looky here, there is also a specification for the distance from the casehead to a .400" datum on the cartridge shoulder. They don't call it "cartridge headspace" but I do because it is fewer words.


If I am loading mixed brass, it is probably not for serious target shooting, so I size the dickens out of it to be sure it all chambers freely. Good enough for plinking, 3-gun, or offhand practice where the target is large.
I am more careful loading same lot number brass for small group/high score.

[cw308]

Jim
Do you have a go gage ? I found it helpfull.

[RC20]

True cam over is what you get when you screw an RCBS die into a RCBS press the specified 1/4 turn.

I don't own any other preses (Junior and two RCs) - but the die mfgs say the same thing (up to 1/4 turn) which I don't do.

I don't do that.

[cw308]

RC
I only remove the slack , once it stops it stops why go any further .

[hounddawg]

@CW- yep. I set the barrels for GO gage headspace, add a brass .003 shim to the GO gage at the bolt end and make that my NOGO length. Then set the sizing die to GO gage length. Gives me .002 - .003 clearance on my sized rounds and I can swap the same cartridge between guns when I have them barreled for the same cartridge.

consistency, that is what it is all about. Like you I have no idea why anyone would need to cam over to size a standard case. I just FL sized 75 .260 cases this morning, all are perfectly sized and not once did I cam over the press

[F. Guffey]

True cam over is what you get when you screw an RCBS die into a RCBS press the specified 1/4 turn.

Not true! In the early 30s a company described the function of their tool, they described the function as 'leaver lock'.

A reloader with minimum shop skills should have the ability to measure the amount of cam over in thousandths. I have had 5 Rock Chuckers, I modified one to cam over; the other 4 are not cam over presses.

One more time: I have two Rock Chuckers with Piggy Back 11 attachments; the Piggy Back 11 attachments is designed to auto advance meaning the ram can not reverse directions. Starting over for reloaders that are shop skill challenged; The ram on a cam over press goes up and stops and then changes directions (that change in directions is the origin of the word 'bump')

The ram bumps on the way up and again on the way down if the reloader understands the ram must travel up before being lowered (on a cam over press).

Back to the auto advance, if the ram changes directions the one way clutch in the Piggy Back 11 attachments prevents it (from reversing directions).

F. Guffey

[cw308]

Guffey
Why would you spend time modifying a RockChucker press to cam over. I don't have your background in machinery , maybe you just like to tinker , I could see that . But in accurate reloading I can't see any good in stressing something . My way of thinking a brass case against a steel rod 1" thick is no challenge so why not do it with the right equipment. I size like hounddawg never had to cam over and I'm turning out accurate reloads . I'm not into chronograph SD/ ES or XYZ my group let's me know what works . With the me factor added in with my reloading and shooting , would neck turning make my groups any tighter . I think it may just come down to , some just like to tinker . I like to keep it simple but accurate .

[cdoc42]

I'm trying to follow this discussion and a lot of it is over my pay grade, being a chemist rather than a machinist or engineer, but let me ask what might be a simplistic question.

Isn't it the object of RCBS instructions to cam over the case to ensure the resulting full-length resized case will fit all rifles in that caliber? If I want to set the shoulder back .002" I follow the RCBS instructions, then back the die out, re-measuring the shoulder setback until I reach my goal. At that setting the cases may not chamber in another rifle of the same caliber. Or I am I not even in the same ballpark in this discussion?

As well, the press is attached to the wooden bench. Isn't it likely that the bench attachment will give in to the force of over camming before the press linkage does?

[F. Guffey]

RC
I only remove the slack , once it stops it stops why go any further .

I am convinced adjusting the die to the press is beyond most reloaders ability to understand.

Again, my favorite cases are cases that are too long from the shoulder to the case head meaning the case is too long from the shoulder to the case head to allow the bolt to close. Manufacturers of components do not sell cases to reloaders that know and understand what they are doing so they sell cases that are considered minimum length or cases that are full length sized.

Many times I have asked where did the 'magic .002"' come from.

When a reoader adjust the die to size the case to minimum length or full length sizes the case the die is adjusted down to the shell holder on a non cam over press; after contact the die is lowered .017" or as we say 'lowered/turned 1/4 turn. If the press is a cam over press the amount of cam over must be added to the 1/4 turn. That would be .017" plus cam over. No one measures cam, if they did and they were using a Rock Chucker they would know the Rock Chucker does not cam over. The Rock Chucker goes into a bind when the linkage makes contact. The ram is kicked forward at the top and back at the bottom so if I had to describe the Rock Chucker I would say it is a 'BINDER'; when the linkage bottoms out it goes into a bind.

And then there is the infatuation with the head space gage. If the reloader could verify the head space gage they could determine the head space gage is .005" longer than the minimum length/full length sized case. To verify the die simply remove the primer punch/neck sizer assemble and then drip the head space gage into the die. For the 30/06 die the head space gage should protrude .005" from the die.

But there are layers and stacked stuff that must be considered. If the die is adjusted to restore the case to minimum length/full length sized the die must make it down to the top of the shell holder, that is the part that is impossible to keep up with. That is when the case has more resistance to sizing than the press, die and shell holder can overcome.

When sizing the case for minimum length or full length sizing the die must be lowered when the case has more resistance to sizing than the press can overcome; so? It becomes necessary to add an additional 1/4 turn to the 1/4 turn the reloader starts with.

A reminder: My favorite shell holder is the RCBS shell holder because it fits like a hand me down shirt; it fits only where it touches. And again I can reduce the length of a case from the shoulder to the case head .010" by adding a .010" shim between the deck of the shell holder to the bottom of the case. So if I need a special shell holder I know how special it has to be. I know; there is Redding special shell holders, problem, the Redding only increases the distance from the deck of the shell holder.

F. Guffey

[Reloadron]

Going back a decade here in this forum:

We have this

Just in this forum there is likely a dozen threads on the subject over about as many years and each thread always ends up looking just like this thread. Just in the very beginning of this thread there were links to two conflicting articles by two pretty well known writers on the subject. A simple Google of the subject matter will yield God knows how many discussions on the subject and for the most part they look very much like this thread.

Just do whatever works for you as I really doubt there is a correct or incorrect way to resize a case short of destroying the thing or doing irreparable damage to your press. While I have several presses and like many a pile of assorted gauges I tend to gravitate to single stage and while I like my old Lee "O" press which is an aluminum frame I like my Rockchucker likely the best since I don't have a Co-Ax which I am sure I would love. I also as to gauges like my RCBS Precision Mics a little more than my Hornady Lock and Load gauges. All of which is just a matter of personal like.

The end of this is always going to be what works best for an individual and the individual knowing best how to use the tools, be it a press or gauge which works best for them.

Next year, when the subject surfaces again we can all enjoy a rerun of what seems to be an unending saga.

Ron

[F. Guffey]

As points of reference, I checked four presses for cam over. Neither a Rockchucker from the 1980s, a Rockchucker from about 2010, nor a Lee Classic Turret from about 2010 cammed over. A Hornady AP Press from about 2013 had a small amount (less than 0.002") of cam over.

Thank you BBarn; I feel like the Indian of many years ago, it was close to 1816 when the Indians had to make a meeting they were not prepared for so they went to Canada and returned with an Indian no one liked. to make it understood and clear to all the Indians reminded him his own people put him on trial and found him guilty.

His confidence builder came in his response; he acknowledge he lost but he made it very clean when he started all of the Indians were against him and when finished one of them had doubts about his guilt so? He took exile in Canada. It was not easy being him; the Indians did not like him and the white guys hated him.

F. Guffey

[F. Guffey]

Next year, when the subject surfaces again we can all enjoy a rerun of what seems to be an unending saga.

If I tell you a chicken dips snuff please do not argue; first! Catch that pullet and check under its wings to determine where she carries her can. The problem with many reloaders is about time they have invested in something that did not happen does not happen. And then there is credit, we all know about the shooter that took himself too serious and claimed the case has head space. At the time I do not believe he was familiar with SAAMI.

He argued and then called SAAMI, again I am sure they were impressed with his shooting but SAAMI is the one that does not list case head space in their case drawings. I do not have trouble with accepting SAAMI because without SAAMI we have reloaders that take themselves too seriously and then start making this stuff up.

And then there was a member that reported me to RCBS; the tech. person gave the complainer a phone number and an extension with his name. All I have tried to do is get reloaders to push themselves away from the keyboard.

I have a Rock Chucker attached to a stand, I also have one that is in a cabinet, I also have one that is attached to a Piggy Back 11 attachment, The attachment has a one way clutch; I also have a spare one way clutch.

F. Guffey

[cw308]

I size my cases to what works best in my chamber , I know my chamber length and I size accordingly.On long cases as F. Guffey posted I wouldn't size back to spec but to .001 - .003 depending on what it's used for . No need for cam over but to me that chamber was cut too long . Long or short chambers what is the point in cam over . Sorry to beat a dead dog to death but I see no good in cam over . Guff I'm getting like you making a short story long . Always good talking gun stuff though no matter how old the subject is .

Chris

[Metal god]

I think the issue here is people stuck on the cam over thought and not what it signifies . All cam over is asking the reloader to do is make hard contact between the shell holder and die . If I adjust the die as RCBS and Redding for that matter instruct in my Lee classic turret press . I will not have cam over because it's impossible to cam over a Lee CTP . I will however get hard contact between die and shell holder resulting in the same sized case as if I sized it in a press with cam over .

Yes the instruction that are written that way are to ensure a case sized this way will chamber in any factory SAAMI spec chamber . It is not to ensure best fit for "your" chamber .

Here is why I ran those tests 5 years ago I explained earlier .

These case head separations were only after my third reload of these cases



This was do to adjusting the die as instructed by Redding and using a standard shell holder . I don't remember the actual number but I had something like .008+ of head clearance . Meaning ( ball park numbers not actual measurements ) my sized case measured 1.624 and my fired case measured 1.632 . That was allowing the web to stretch .008 each time the case was fired . After .024 of stretch the cases failed .

It was then I started disregarding the instructions , which is not always that easy to do when reloading . Disregarding some instructions can get you killed so I was a bit hesitant at first not knowing at the time if die adjustment instructions was one of them that could get you hurt .

That was also around the same time I started to understand sizing the cases minimally. When I was trying to only bump my shoulders .002 some would bump more while others would not bump at all. At the time I was not measuring my head to datum distance . I did the old size a fired case minimally then try to chamber . If I felt resistance I screwed the die down a tad more , sized and chambered again . Repeat until the bolt closed feely then lock the ring down . However I found later some cases would chamber with ease while others would have some resistance still when closing the bolt after sizing a few hundred cases at that die setting . It was then I learned my Hornady press linkage deflects a lot and was the primary cause of those inconsistencies as described above and in my post with the press deflection pics .

The only way I was able to stop the inconsistencies while backing the die off a standard shell holder deck hight when using my Hornady press was to start using Redding competition shell holders . They allow me to size my cases that .008 longer while at the same time forcing all that deflection issues out of my press .

I'm sure other presses don't have as much flex as my Hornady does and might be why some of you don't seem to have the same issue or don't notice it . I however do have an issue with press deflection be it in the frame or linkage makes no difference to me . Although it's my belief it's more in my linkage then anything else .

All that said , my Hornady press is designed to cam over or at least it's able to do so . I can set the die down lower to not allow for cam over and if I use the comp shell holders my cases come out the same as if I cammed over as long as the die and shell holder makes hard contact with each other .

As to press deflection likely only being in the linkage . I'll go with maybe most of it is in the linkage but there are many presses out there that the press frame and or other parts that are not the arm linkage that allows for or do simply flex . The little cheap Lee press will flex but the type that will flex the most and maybe flex is the wrong word is C type turret presses . Namely the Redding T7 press flexes for sure do to the open face design , tolerances in the tool head and the long cantilever design of the 7 station press head .

I know the T7 has this issue because I helped a guy out that was having the same issue with his T7 I was having with my Hornady single stage . He would get very consistently sized cases from head to datum point if his dies and standard shell holder made hard contact . However that setting sized his cases .006 more then what he wanted which was a .002 bump . When he backed the die off the shell holder to size the cases correctly . The cases started being sized very inconsistently . To get every case to bump at least .002 some were bumped .004+ do to the press flexing . I recommended he try the competition shell holders and it resolved his problem .

I'll add that I don't "need" the comp shell holders to size my cases . I use them to get a more consistent sized case from case to case . I'll add I load for multiple 308 rifle with all having slightly different headspace dimensions and never need to adjust my die to get my .002 bump regardless of the rifle I'm loading for or cases I'm sizing or times fired . If it's the longer chambered rifle I use the .008 comp shell holder and if it's the smaller chambered rifle I use the .004 shell holder never needing to adjust the die it self and still get the perfect .002 bump . I have not adjusted my lock ring on my 308 or 223 sizing dies in years just insert the correct shell holder for the rifle and or cases being sized and I'm gtg .

If anyone's wondering how could write such a lengthy post when football is on . Let's just say I stopped watching my charges somewhere in the first half

[cw308]

I appreciate your time and posts Metal , always a good read . I'm hooked on talking gun stuff with my friends on thefiringling . Be Well.

Chris

[F. Guffey]

I size my cases to what works best in my chamber , I know my chamber length and I size accordingly.On long cases as F. Guffey posted I wouldn't size back to spec but to .001 - .003 depending on what it's used for . No need for cam over but to me that chamber was cut too long . Long or short chambers what is the point in cam over . Sorry to beat a dead dog to death but I see no good in cam over . Guff I'm getting like you making a short story long . Always good talking gun stuff though no matter how old the subject is .

I ask: Again and again and again etc. where does (did) the magic .002" come from. I believe your arms are going to be worn out petting your friends and your self on the back before you ware out your arms sizing cases on your presses.

If you are going to eliminate the die from contacting the shell holder you will sacrifice leverage. When you adjust your die to size the case you are controlling the length of the case from the shoulder to the case head.

One more time and again and again and again I have one rifle that has a chamber that is field -gage length plus .002". WHAT DOES THAT MEAN? ! It means the clearance in the chamber when firing minimum length/full length sized case or over the counter ammo or factory loaded ammo the clearance is .016".

And then? WHAT TO DO? I size 280 Remington cases to 30/06 with a gap between the bottom of the die to the shell holder .014". The 280 Remington case is .051" longer from the shoulder of the case to the case head than the 30/06 case from the shoulder to the case head.

And now? I do not believe you understand what happened when the press reduced the length of the case .014"

I backed the die off .014" if the press was a non cam over press, if the press was a cam over press I could subtract the amount of cam over from the .014".

Again I had a friend that adjusted his A2 cam over press with 1/2 additional turn after contact with the shell holder meaning he lowered the die .044". his press by design had a cam over of .017". When lowering the ram he had to raise the top of the press .051".

F. Guffey

[David R]

All I do is turn the die in a little at a time until the case fits in the bolt action with little or no resistance.

Call it what you like. It’s not going to hurt the press.

David

[Metal god]

All this got me thinking I know ! Have presses always been able to cam over ? I know some don’t and may never been built to do so but since there has been presses for reloading has there always been a type that cammed over ?

My thinking is maybe the die instruction have been around much longer then the cam over press ??? May be why following the die directions when using a pess that cams over puts to much stress on that type of press ??