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Old January 10, 2019, 04:52 PM   #1
hounddawg
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Don't stress your press

why you should not "cam over". This guy has a lot better grasp on word smithing than I do and explains in detail exactly why it is a bad practice

http://www.mssblog.com/2016/04/14/ca...-it-just-dont/
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Old January 10, 2019, 05:02 PM   #2
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Good read
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Old January 10, 2019, 05:42 PM   #3
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I have always enjoyed reading material by Glen D. Zediker as he does a good job of presenting his material and backing up what he has to say be it with his personal experience or well documented facts. His now old book The Competitive AR 15, first printing July 2008 The book is extremely well written and a wealth of knowledge for working on match service rifles AR 15. I also got a lot from his article Reloading for the Match M 14.

As to cam over he again does a good job of explaining what is going on and press linkage as well as why he sees it as a bad idea.

Ron
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Old January 10, 2019, 07:00 PM   #4
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Would putting a zero stop before the bottom of handle travel (ram raised) be a good idea?
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Old January 10, 2019, 07:27 PM   #5
F. Guffey
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Some presses do not cam over, they just go into a bind, for years I suggested reloaders learn to use the feeler gage; I did not give up but the feeler gage became something reloaders could not master.

I modified a Rock Chucker to cam over.

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Old January 10, 2019, 08:09 PM   #6
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I will ask again , when you buy a rifle that shoots store bought ammo and you get into reloading , why would you have to cam over your cases ? I never had to.
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Old January 10, 2019, 08:16 PM   #7
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For me it's pretty easy to feel when I hit TDC and a good rule of thumb is if it does not feel right just don't do it. Bear in mind I just reload up to .308 and don't wildcat or do anything fancy and could easily get by with a entry level Lee press. The most force I will ever need is enough to full length size a .308 or 30-06


Quote:
I will ask again , when you buy a rifle that shoots store bought ammo and you get into reloading , why would you have to cam over your cases ?
CW pretty much nails it
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Old January 10, 2019, 08:54 PM   #8
tangolima
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Cam-over press gives you infinite mechanical advantage when the ram is at its highest point (before the handle goes all the way down). Nothing wrong with that, and it doesn't have to hurt your press.

The definition of camming over in the article is different. It refers to setting the die too low and forcing it. Of course it is a bad thing to do. But it has nothing to do with cam-over type of press.

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Old January 10, 2019, 09:19 PM   #9
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^^^^ +1
Some dies and cam over are the norm......so it all depends
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Old January 10, 2019, 09:57 PM   #10
cw308
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I know how cam over works . Why would you have to cam over your cases . Is there a problem with your chamber or the die . In most cases when your F/L die is adjusted to bottom on shellholder you would be over sizing the case .
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Old January 10, 2019, 10:00 PM   #11
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cw 308:
Quote:
I will ask again , when you buy a rifle that shoots store bought ammo and you get into reloading , why would you have to cam over your cases ? I never had to.
Using 308 Winchester as an example. I full length resize and have several sets of dies but since I may use the loaded ammunition in any of 4 rifles including 2 semi-auto and two bolt guns I make it all the same so what I load will shoot fine in any of my rifles. I also do not run my dies down that extra 1/8th to 1/4 turn. Simply because I never had a need to. I get my case head to shoulder datum at 1.630" and that is all I need.

Now as to Glen Zediker's article that is how I do it simply because it works fine for me and my brass.

Enter Chuck Hawks another pretty well known gun writer and his article How to Adjust Reloading Dies By Chuck Hawks. Hawks tells you straight up he is parroting RCBS loading die instructions which he is. He reads in part:
"Here is how to adjust the resizing die to full length resize cases. First, run the ram to the top of the reloading press stroke with the proper shell holder installed. Second, screw the resizing die into the press until it stops against the elevated shell holder. Third, all play must be removed from the system. To do this, lower the ram and turn the die 1/8 to 1/4 turn farther into the press. Check the adjustment by returning the shell holder to the top of its stroke--you should feel the press cam over center. Now set the large lock ring and your die is adjusted to properly full length resize cases".

Standard loading dies have a 7/8 - 14 thread so at 14 Threads Per Inch each full turn of the die is 1/14 inch or 0.0714" and 1/4 turn would be about 0.0179". Unclenick has published some pretty neat templates which can be printed out and he might provide that link again. Also, JMorris has demonstrated a neat fixture to measure die travel. The numbers I just used are approximate as they do not account for any backlash in the threads.

Anyway, all interesting but what it comes down to is Zediker uses one method, all well defined and explained and Hawks uses another method also well defined based on RCBS die instructions. Me? I know where I want my cases to be and I take that road and when both roads get me there I take the road of least resistance.

Ron
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Old January 10, 2019, 10:16 PM   #12
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Any press that has a linkage where the ram/linkage relationship can go over center will have “cam over”.

Binding things can be done on any press.
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Old January 10, 2019, 10:50 PM   #13
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Quote:
I will ask again , when you buy a rifle that shoots store bought ammo and you get into reloading , why would you have to cam over your cases ? I never had to.
Because that is what they tell you to do. 1/8 to 1/4 Turn.

We assume the machine makers know more about them than we do when we start.

Only places like this and some publications now say NO.

Most of my life when an mfg has given me a spec I did it to that spec.

This is a rare field but all too common (does any press or die mfg not say at least 1/8?)

A few times from experience I have concluded the mfg had their head someplace dark and smelly.

Why this perpetuates in our filed of interest I have not a clue.

When I started loading cases more than 8x (my brother and I) he went looking for answers and found them. I have followed what he found.
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Old January 11, 2019, 04:29 AM   #14
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I cam over on some dies because the instructions said to, but I don't go ridiculous. I will say that I have a rifle that feeds factory that won't eat my full length resized brass, but has to be small base resized due to what I am guessing is a tight chamber. Only one I have ever run into that does that. And I followed RCBS instructions on how to set that one up to. Been using the same RCBS RS press for a few years now with wonderful results.
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Old January 11, 2019, 08:52 AM   #15
cw308
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It looks like the only reason you have to cam over your cases is the chamber is longer then spec.? When factory rounds fire , most are .003-4 over sized anyway . With a properly sized chamber I can't see any reason to cam over . Why do people cam over .
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Old January 11, 2019, 08:57 AM   #16
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once that steel shell holder sitting on a steel ram hits the bottom of a steel die how much farther can do you think you push it into the die ? Does your press crush the die so it is a few thousandths shorter every time you size cases? or does your shell holder get a few thousandths thinner? Maybe it is the ram that shrinks a bit

maybe I am missing something here but seems to me that if the shellholder hits the bottom of that die and the die is securely threaded into the press the ram is not going to go any farther up no matter how much you flex the linkage
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Old January 11, 2019, 09:20 AM   #17
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It’s pretty hard to not stretch & compress a press when sizing cases even if your not using an over center linkage. Some may be harder to measurehe amount (built more ridged) but if you have the right tools ou could see it.

It doesn’t take much to see it on an aluminum O frame press, even with lubed .223 cases.

https://www.youtube.com/watch?v=i22Jb5jEBiQ
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Old January 11, 2019, 10:53 AM   #18
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I’m going to read the article before commenting more but I cam over every single time I size a bottle neck rifle case because the shell holders I use require it . I use Redding competition shell holders . If the die and shell holder don’t bottum out on each other there is no need to use them .

EDIT : Well it only took a minute of reading to see this guy has no clue what he's talking about .

Quote:
Going over the previous material on using a cartridge case headspace gage to determine sizing die positioning to get the correct amount of case shoulder setback,
Thanks to Unclenick and Mr Guffey we all now know when so called experts use words and terms like this when it comes to reloading . They clearly don't know what they are talking about . So I have chosen from now on to join them in pointing out how uninformed people are when using these terms and that we should not listen to people that clearly don't understand what they are talking about .All they ultimately do is confuse the new reloader by using these terms when all the new reloader is doing is trying to find the correct information here at TFL . If the internet experts don't understand the most basic things such as what headspace is or that it's impossible to "set" a shoulder back . Who knows what other misinformation they are telling us .
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Old January 11, 2019, 11:19 AM   #19
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I've often wondered why die makers don't build more adjustment room into their dies. I understand SAMMI spec and all that, but I shouldn't have to punish my press to size a cartridge for my particular rifle. Because I largely shoot levers and autoloaders, I tap the shell holder, technically camming over, but I don't have to force it.
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Old January 11, 2019, 11:36 AM   #20
hounddawg
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thanks guys for explaining how a when you set the die to contact the shell holder you can actually make it go farther into the die by compressing either the 10 inch long 1 inch diameter steel ram and that 1 inch thick cast iron press !

Also thanks MG for explaining how it is only my imagination when I put a fired case into that die and after sizing, with no cam over by the way, that shoulder isn't really coming out .004 closer to the case head, that is only my lying set of calipers trying to pull one over on me.

Maybe if I buy a $1000 set of calipers I can find a honest set or should I buy a $400 press with a elastic frame. A sansabelt press? Some hard rubber shellholders might be a cheaper answer?
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Old January 11, 2019, 12:40 PM   #21
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No problem hawnddawg , happy to help . It’s important we all know what the TRUTH is . The great thing about the truth is you can’t be considered a troll or to be disrupting a thread as long as what you say is technically correct regardless of how irrelevant it is to the thread .
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Old January 11, 2019, 01:26 PM   #22
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Did an experiment with some old Hornady .260 Rem brass, my normal S bushing FL die and a Redding body die.

Using my lying calipers and a .400 comparitor in my Hornady case gage I did some measurements. Before sizing the distance from base to case mouth was 2.024 inches and the distance from base to shoulder datum was 1.627. I took one piece of the brass and sized it with my bushing die to 1.624.

Then I took a second piece of brass and replaced the bushing die with a body die since I do not want to mess with the adjustment on my normal die. I set the body die to where I was getting sized brass with the shoulder set back to 1.624 and took feeler gages and tried to slip them between the top of the caseholder. I came up with about .009 clearance. After I lowered the ram I turned the die down 1/2 turn and this time went camover. Clearance between the case holder was zero this time and a measurement of the shoulder to base was down to 2.014. So when you camover all you are doing is forcing the case farther into the die. This time I could not get a piece of .001 shim stock between the die and the shellholder

I run tight chambers, headspace wise. I set them up to GO gage + .003. So my normal sizing only sets the shoulder back .003 to the same measurement as my GO gage.

I also found where that brass went, when that shoulder moved back at least some of it traveled to the neck and lengthened it .003. Case head to case mouth went from 2.024 to 2.027

So back to the question" do you need to cam over". Just speaking for myself no, I can get by without stressing my press. Whether you need to is a question only you can answer. If you are running a loose chamber and getting case stretch of .007 maybe you do. It probably also adds to the consistency if you are prone not to not forcing the handle all the way down when operating the press. The little bump in the stroke being a tactile reminder
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Old January 11, 2019, 01:39 PM   #23
David R
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If I don't adjust to cam over, my brass will not chamber. I just called it proper adjusting.

MY opinion. The press was made that way. No damage will be done.

I am a mechanic and welder.

David
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Old January 11, 2019, 01:51 PM   #24
hounddawg
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What type press is it David ? I don't think it would destroy a press in less than 100 years of operation, it just adds some stress on the linkage pins. On a automated assembly you would see wear over time if you were pumping out 10K rounds a day, but for home use I doubt you could wear one out in 100 years. As a lifelong mechanic/machinist/electrician I avoid putting any more stress on my tools than I need to but that's just me and my cases come out just fine without it so why do it
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Old January 11, 2019, 02:56 PM   #25
David R
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As far as I am concerned, when the linkage goes over center, it just makes sure every stroke is the same.

I have a rock chucker and a Dillon 550. Any press I have used goes over center. Its made that way.

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