To cam over, or not?

The #1 community for Gun Owners in Indiana

Member Benefits:

  • Fewer Ads!
  • Discuss all aspects of firearm ownership
  • Discuss anti-gun legislation
  • Buy, sell, and trade in the classified section
  • Chat with Local gun shops, ranges, trainers & other businesses
  • Discover free outdoor shooting areas
  • View up to date on firearm-related events
  • Share photos & video with other members
  • ...and so much more!
  • Psode27

    Expert
    Rating - 100%
    4   0   0
    Jan 23, 2011
    1,234
    38
    Rochester
    In my research to find out if I need small base dies for my 223 (several ARs), I kept running into people insisting you needed them, or very opposed to them. Those who said you didn't need them said sometimes mentioned that those who have problems with a standard die, don't have their dies set up correctly, and weren't letting their press cam over.
    This leads me to another layer of research... Some say you shouldn't let your press cam over, some disagree.
    To me, it shouldn't matter that much. I would THINK that as long as your die kisses your shell holder, it should be good. What is the "official" INGO opinion? I'm new at this...
     

    1911ly

    Grandmaster
    Site Supporter
    Rating - 100%
    6   0   0
    Dec 11, 2011
    13,419
    83
    South Bend
    If your brass is feeding fine then you are doing what works. Maybe it depends more on the brand of dies? I haven't had any issues just following the manufactures recommended setup. I know I tend to over cam in a hurry. It's only bit me in the ass once on 8mm Mauser brass. I pushed the shoulder back, then I read the manual :ugh: duhh. I always read the manual now.

    If the manual says adjust until it touches the shell holder ( then if I remember some of my dies say to turn a bit more) I think over camming a little is harmless.

    My Lee uses a breach lock bushing setup. I like it. RCBS rock chucker has something similar. And Hornady dies and others have the split nut the the allen screw to hold/lock the adjusting nut in place. I like that. so I don't have to adjust the die each time.
     

    billybob44

    Master
    Site Supporter
    Rating - 100%
    383   0   0
    Sep 22, 2010
    3,426
    27
    In the Man Cave
    Some Yes--Some No....

    This is another one of those "Each to His Own"...

    For ME---I use case gauges. Dillon in .223, .308, and .30-06--Wilson for the others.
    These case gauges have two steps. I adjust my Full Length size die to push back the shoulder to where the case drops BELOW the top step, and just ABOVE the bottom step. In SOME cases this DOES take the "Cam Over" operation of my old RockChucker.....The .270 Winchester comes to mind, and SOME .308/.30-06's.

    Most of the time there is a slight die adjustment when going from Military to commercial brass to obtain this adjustment.

    For ME--by doing it this way my loads will fit/cycle most ANY chamber, be it mine, or a friend/relative.

    YES, when I want to get the most accuracy out of once fired cases, I neck size to be fired in THAT rifles particular chamber.

    Some even get the Redding Competition Bushing Die treatment...Bill.
     
    Last edited:

    Psode27

    Expert
    Rating - 100%
    4   0   0
    Jan 23, 2011
    1,234
    38
    Rochester
    Thanks for the replies! It makes sense that everyone has there way. Not having done a ton of reloading, and not being able to easily test loads, I was just looking for some more opinions. The more I read into this stuff the less straight forward things become, rifle brass anyway.
     

    EvilKidsMeal

    Master
    Rating - 100%
    14   0   0
    Feb 11, 2010
    1,719
    2
    Highland
    I would say it just depends on the equipment. The manual for my Hornady single stage says the press is made to slightly cam over in order to exert maximum force with less effort during sizing.

    For die setup, though, it specifically says the die be screwed down until it touches the shell holder at the top of the ram stroke, NOT at cam over. This allows cam over of the press though.

    So I would see if your instructions mention cam over.
     

    Broom_jm

    Master
    Rating - 0%
    0   0   0
    Dec 10, 2009
    3,691
    48
    Brass should be sized until it fits in whatever chamber(s) its going to be fired from, and no more than that. I have chambers where camming over the press is necessary to reduce the size of the brass enough to fit the chamber. Most chambers don't require that I cam over during resizing.

    Since you're looking at loading for several different AR's, and almost certainly won't want to keep brass separated, I would plan on setting your die/press to cam over, slightly. This will help ensure than any piece of brass you size and load will run in any of your chambers. It isn't complicated, it's a function of your shooting choices. If you had three different bolt-action 30-'06 rifles and wanted the very best accuracy from each, THAT might get complicated. :)
     

    ROLEXrifleman

    Master
    Rating - 100%
    54   0   0
    Feb 7, 2009
    1,767
    84
    NW Indiana
    Having the press cam over means the ram has reached the top of its stroke. Set up the press by first running the handle till the lever cams over, then run the die till it fits snug against the base. You'll be gtg after that for sizing with a standard base and die
     

    Clay Pigeon

    Shooter
    Rating - 100%
    6   0   0
    Aug 3, 2016
    2,740
    12
    Summitville
    So much of the reloaders against using small base dies comes from reloaders that dont have more than one rifle in the same caliber, or they have always used dies made from companys like Lee and Dillon that dont make small base dies. Guess why they dont ?
    Because the dies in the calibers that you can get a rifle in a pump, lever and auto they make are for the most part, small base dies.
    If loading for multiple AR's and ammo gets swapped between them,
    Using a small base die will cure having ammo that wouldn't fit all but one rifle.
     

    Broom_jm

    Master
    Rating - 0%
    0   0   0
    Dec 10, 2009
    3,691
    48
    Having the press cam over means the ram has reached the top of its stroke. Set up the press by first running the handle till the lever cams over, then run the die till it fits snug against the base. You'll be gtg after that for sizing with a standard base and die

    Not exactly. The ram reaches the top of its stroke, or should, ever single time you operate it, for any part of reloading. When a press cams over, it is using the mechanical leverage of the press to actually make contact with the mouth of the FL sizing and THEN move just a little more. There is a small amount of resistance in this process, ensuring the brass is sized as much as possible, in that die. For those with the knowledge of feeler gauges and milling shell holders, camming over is usually not necessary.

    So much of the reloaders against using small base dies comes from reloaders that dont have more than one rifle in the same caliber, or they have always used dies made from companys like Lee and Dillon that dont make small base dies. Guess why they dont ?
    Because the dies in the calibers that you can get a rifle in a pump, lever and auto they make are for the most part, small base dies.
    If loading for multiple AR's and ammo gets swapped between them,
    Using a small base die will cure having ammo that wouldn't fit all but one rifle.

    Small base dies size case heads smaller than SAAMI specifications. Some companies make such dies, while others make their dies so that brass is sized to the small side of spec. I have Hornady dies that size case heads to the smallest SAAMI spec, and that's a problem...cases wallow around in the chamber and accuracy suffers. The only two cartridges I would ever consider using small base dies on are 223 and 308. All others I would size minimally, as that is best for both case life and accuracy.
     

    Clay Pigeon

    Shooter
    Rating - 100%
    6   0   0
    Aug 3, 2016
    2,740
    12
    Summitville
    Small base dies size case heads smaller than SAAMI specifications. Some companies make such dies, while others make their dies so that brass is sized to the small side of spec. I have Hornady dies that size case heads to the smallest SAAMI spec, and that's a problem...cases wallow around in the chamber and accuracy suffers. The only two cartridges I would ever consider using small base dies on are 223 and 308. All others I would size minimally, as that is best for both case life and accuracy.

    Hogwash JM, This is exactly how incorrect information gets started.
    Small base dies will size the main body of the cartridge at best 2 thousands smaller than a regular full length die, That's it at best.
    Do yourself a test, take a few Factory cartridges and measure them at the neck, at the top of the body under the shoulder and at the base just above the rim.
    Then pull a bullet and run it through a full length die, and then measure it.
    It will be untouched you will find.
    Then run it through a small base die and measure it, again you will find it is untouched.
    You will be surprised that you will find is that the factory cartridge will measure about 5 to 7 thousands smaller than a full length die and 3 to 7 thousands smaller than the same brass that has been sized with a small base die.
     

    Psode27

    Expert
    Rating - 100%
    4   0   0
    Jan 23, 2011
    1,234
    38
    Rochester
    So, for the end result of making lots of 223 that will shoot flawlessly through 8-10 different ARs with factory ammo reliability, would you use a SB die? The two dies I was considering (RCBS X-dies) are sold out in standard and SB, so I haven't been able to buy anything yet. This gives me further time to over-analyze what many would consider a mundane purchase... :)
     

    Broom_jm

    Master
    Rating - 0%
    0   0   0
    Dec 10, 2009
    3,691
    48
    Hogwash JM, This is exactly how incorrect information gets started.
    Small base dies will size the main body of the cartridge at best 2 thousands smaller than a regular full length die, That's it at best.
    Do yourself a test, take a few Factory cartridges and measure them at the neck, at the top of the body under the shoulder and at the base just above the rim.
    Then pull a bullet and run it through a full length die, and then measure it.
    It will be untouched you will find.
    Then run it through a small base die and measure it, again you will find it is untouched.
    You will be surprised that you will find is that the factory cartridge will measure about 5 to 7 thousands smaller than a full length die and 3 to 7 thousands smaller than the same brass that has been sized with a small base die.

    Are you asserting that factory case heads are anywhere from 3 to 7 thousandths smaller than the chamber?

    Properly made and used dies size a case minimally. Like I said before, some companies make their dies to size a case head down to a nominal dimension, per SAAMI spec. It has been my experience that once-fired cases that are run through a small base die are sized smaller than they would have been in some other dies. That's why they call them small base dies.

    If the OP is loading for half a dozen different AR's, a small-base die is probably a very good idea.
     

    jblomenberg16

    Grandmaster
    Rating - 100%
    67   0   0
    Mar 13, 2008
    9,920
    63
    Southern Indiana
    So, for the end result of making lots of 223 that will shoot flawlessly through 8-10 different ARs with factory ammo reliability, would you use a SB die? The two dies I was considering (RCBS X-dies) are sold out in standard and SB, so I haven't been able to buy anything yet. This gives me further time to over-analyze what many would consider a mundane purchase... :)

    FWIW, I'm using standard RCBS dies for just about all of my loads and my rounds fit fine in multiple AR's.

    Good info was posted above on the mechanics of camming over. To me its similar to finding TDC on an engine. To do it right you actually go a little past TDC while using a dial indicator and look for the "dwell" in the middle, usually seeing the piston dropping a little and then coming back to it to get true "dead nuts TDC." In addition to the mechanical advantage of camming over, doing so when you set up the die means you'll definitely get the full stroke of the press and maximum travel. After camming over the ram will likely have gone just past "TDC" and by screwing the die down to touch at this point (if that is the recommended setting for the die) ensures that if you go through the full range of motion of the press handle, that you'll never come up short. It also will ensure that the small amount of "slop" in the press linkages, etc. doesn't result in a short stroke.
     

    Clay Pigeon

    Shooter
    Rating - 100%
    6   0   0
    Aug 3, 2016
    2,740
    12
    Summitville
    Are you asserting that factory case heads are anywhere from 3 to 7 thousandths smaller than the chamber?

    Properly made and used dies size a case minimally. Like I said before, some companies make their dies to size a case head down to a nominal dimension, per SAAMI spec. It has been my experience that once-fired cases that are run through a small base die are sized smaller than they would have been in some other dies. That's why they call them small base dies.

    If the OP is loading for half a dozen different AR's, a small-base die is probably a very good idea.

    Actually this is what you said and its just not true.
    Small base dies size case heads smaller than SAAMI specifications. Some companies make such dies, while others make their dies so that brass is sized to the small side of spec. I have Hornady dies that size case heads to the smallest SAAMI spec, and that's a problem...cases wallow around in the chamber and accuracy suffers :

    If accuracy truly suffers with cases so small with the average / military shooter why does so much factory match grade ammunition do so well shooting in so many guns in the world ?

    Small base dies have there place. And what the OP is asking about, It would fill his need very well. Its simple, factory cases are smaller than any die available over the counter, small base dies included.

    Edit.
    Chambers have not been mentioned in any of my posts, please dont be like Kut.
     

    rvb

    Grandmaster
    Rating - 100%
    4   0   0
    Jan 14, 2009
    6,396
    63
    IN (a refugee from MD)
    Whether to cam over or not isn't something you should determine by Internet consensus...
    look at your headspace gauges and the ammo in your guns, if your need to push the shoulders requires a little cam over, do it. If not, don't.

    I happen to think I get a little more consistent headspace with a little cam over, especially on my Dillon where the die isn't centered over the ram, so it helps take out some 'slop' in the system....

    -rvb
     

    Psode27

    Expert
    Rating - 100%
    4   0   0
    Jan 23, 2011
    1,234
    38
    Rochester
    Thanks for all of the replies regarding bot SB dies and cam over. I think the post about finding TDC on an engine makes sense. I think as long as you don't go "crazy" a little cam over could be good if only to ensure full sizing.
    When I pull the trigger on my dies I'll be ordering case gauges as well. As said by rvb, I'll probably let what my gauges say drive the boat... I am kinda curious to try a normal FL die and a SB die to see if there is any difference in chambering. Probably something I'll watch for used or something.
     

    Woobie

    Grandmaster
    Rating - 0%
    0   0   0
    Dec 19, 2014
    7,197
    63
    Losantville
    Call me crazy, but I just follow the recommendations of the die mfg. Most will tell you to run the press down to the point it starts to cam over and run the die down until it touches the shell holder. At that point you drop the ram and screw the die in another 1/8th turn to get a slight cam over. If you're down to the shell holder, you can't size any more. The cam gives you the leverage and tactile feedback to know you're in all the way. This is how I full length size.

    I don't neck size with 7/8-14 dies. All of that is done with L.E. Wilson dies and a Sinclair arbor press.
     
    Rating - 100%
    128   0   0
    Jan 28, 2009
    3,656
    113
    Call me crazy, but I just follow the recommendations of the die mfg. Most will tell you to run the press down to the point it starts to cam over and run the die down until it touches the shell holder. At that point you drop the ram and screw the die in another 1/8th turn to get a slight cam over. If you're down to the shell holder, you can't size any more. The cam gives you the leverage and tactile feedback to know you're in all the way. This is how I full length size.

    I don't neck size with 7/8-14 dies. All of that is done with L.E. Wilson dies and a Sinclair arbor press.
    :+1:
     

    Clay Pigeon

    Shooter
    Rating - 100%
    6   0   0
    Aug 3, 2016
    2,740
    12
    Summitville
    Call me crazy, but I just follow the recommendations of the die mfg. Most will tell you to run the press down to the point it starts to cam over and run the die down until it touches the shell holder. At that point you drop the ram and screw the die in another 1/8th turn to get a slight cam over. If you're down to the shell holder, you can't size any more. The cam gives you the leverage and tactile feedback to know you're in all the way. This is how I full length size.

    Its pretty simple isn't it, follow the directions.
     

    Clay Pigeon

    Shooter
    Rating - 100%
    6   0   0
    Aug 3, 2016
    2,740
    12
    Summitville
    Jason here is my response to your PM to me,
    We are not talking about 100 to 300 yard benchrest, F Class nor Creedmore or Wimbledon shooting here, these AR's are not going to shoot Perry.
    Its not a discussion on case life or case head expansion, its a simple topic on what dies are needed for the same cartridges to be used in different AR's.
    And to the general reloading public, Thats what SB dies are for and thats why at least 2 or more die companys make there standard dies on the small side of sammi spec. They will fit just about any chamber.

    And yes i understand case head expansion, thats something that 99.99% of reloaders could care less about. And yes i am also one of those guys with Wilson dies but i use a Harrell Bros combo press.

    You keep changing the topic, i asked you not to be a Kut. :dunno:
    OP sorry to derail your post, i would suggest that you read what rcbs says about there SB dies and then make a decision. :):
     
    Top Bottom