competition shellholders

Discussion in 'Handloading and Reloading' started by CANNONMAN, May 28, 2019.


    CANNONMAN member

    Apr 16, 2014
    I would like some help getting to know more about competition shell holders. These would be for a 6.5 CM. Thanks
  2. Blue68f100

    Blue68f100 Member

    May 25, 2011
    Piney Woods of East Texas
    The shell holders start at +0.010", +0.008", +0.006", +0.004", +0.002", then std . You setup by starting with the +0.010" . As the brass work hardens and resist moving the shoulder back you go to the next size. You can do the same thing with shims under the sizing die, which is a lot cheaper route. If you anneal they are not needed.
    Walkalong likes this.
  3. Walkalong

    Walkalong Moderator

    Nov 20, 2006
    And of course you can always just adjust the die as well.
  4. Chuck R.

    Chuck R. Member

    Jan 23, 2005
    Leavenworth, KS
    I use the die shim method, as stated previously it's cheaper.

    I anneal religiously, but the shims allow me to load for different rifles and not having to adjust the dies. I set my dies up per manufacture's recommendation for FL sizing then back off using the shims to achieve the shoulder bump I'm looking for for that rifle. I simple record the shim used for that rifle.
    Blue68f100 and Walkalong like this.
  5. JimKirk

    JimKirk Member

    Nov 23, 2008
    Nicholls,GA South Georgia
    The nominal thickness for standard shellholder is 0.125" ( dimension Y) ....
    The Redding Competition Shellholders are the amount of INCREASED thickness of dimension Y....

    So dimension Y would be ....
    +0.002= 0.127"
    +0.004= 0.129"
    +0.006= 0.131"
    +0.008= 0.133"
    +0.010= 0.135"

    None of the RCS size a brass as much as does a nominal shellholder that is 0.125" ....

    The folks adding a shim under the brass between the brass and shellholder ...are Decreasing "Y" by the thickness of your shim... and are pushing the shoulder back more ....not less as the RCS do.....

    The folks using a shim(most likely a feeler gauge) between the very top of the shellholder and the bottom of the die ....are just measuring the "gap" ....

    Last edited: May 29, 2019
    Reloadron likes this.
  6. rskent

    rskent Member

    May 28, 2006
    The land of blue sky and sunshine
    I like them.
    I use them for my match 223. Yes, I could adjust the die. But with the competition shell holders I don’t have to. And the adjustment never changes. The brass I prepped this year is the same as last year. No fuss, no muss.
    Toprudder, JimKirk and Walkalong like this.
  7. jmorris

    jmorris Member

    Sep 30, 2005
    I don’t have them, a die adjust guy too, like this.

    JimKirk’s drawings are correct you are not changing the height of the case head, rather putting the shell holder and die in an increasing bind against one another if you started out small, “springing” the frame of the press would result without die adjustment. One should start with the “tall” one and go shorter from there, to prevent damage.

    Would make sense to me because often “crank it down to touch” is often too far, for best brass life, the +.010 would be a better starting point. Could do that with a feeler gauge too though and they are cheap.

    A shim between the case and bottom of the shell holder would raise the case without closing the distance between the shell holder and die though but with opposite results as noted above.

    So how much? Well, I go for “just enough” as it’s reliable and doesn’t over work the brass shrinking it by sizing it too far, just to expand it again upon firing.

    How do I do that? I start by the fun part and shoot some rounds through the rifle. Then I remove the firing pin so it’s just the bolt free to fall in the receiver when it passes the portion for the lugs.

    Start with the die with no decapping pin and raise the ram with fired case in the shell holder, now thread the die down so it is in contact with the case.

    Now take the case and drop it in the chamber and see what it does. The bolt handle will likely be in the “up” position because the case is too long. To solve that you need to lower the die more to make the distance between the shoulder and the head shorter.

    You can measure the distance like above, calculate it by the amount it is turned in the 7/8-14 threads or just “sneak up on it” with slight incremental changes.

    Once you have the distance between the head and shoulder short enough that the bolt handle falls 1/2-3/4 the way “home” you are very close to the spot that will give you max case life and in my experience accuracy, with that chamber. Looks like this.


    If your are loading for different rifles in the same caliber forget all of that. The reason being “tolerance”. SAAMI doesn’t have a head space dimension, rather a tolerance (as is common in all things man made or otherwise imperfect) so you chamber a gun to work with ammunition with in the allowable range. That is “loose” to perfect. If you size your ammunition to the minimum of the allowed specification, now you are really loose as the minimum is the furthest from the maximum. Also known as a tolerance stack.

    It’s not a fluke that the shell holders are up to +.010, happens to be the tolerance of head space for a number of rounds. (The circle X noted dimension for the chamber below).


    With all that hot air, stick a .010” feeler gauge between the top of your shell holder and die, you just made a +.010”, .002 and a +.002, etc. you can get a set at any auto parts store.
    Last edited: May 31, 2019
    JimKirk and Walkalong like this.
  8. Howland

    Howland Member

    Dec 17, 2017
    Upstate SC
    I do this. Each 5° turn of the die is almost exactly 0.001".

    Most die instructions say raise the ram, screw the die down to the shellholder, drop the ram and turn down X/4 turn more.

    I turn it down to the shellholder then back off a quarter turn. Then I size the cases, measure headspace and choose the longest shoulder to work with. If I can feel the additional resistance closing the bolt, I turn down the die 5-10° at a time until I get to target headspace. That is perfect adjustment for that chamber. Competition Dies come in real handy when using the same die to load for more than one chamber without having to adjust your dies.
  9. edwardware

    edwardware Member

    Feb 23, 2010
    In Redding's defense, they will point out that bottoming a Comp Shell Holder on the die rim is more consistent than depending on the ram linkage. They are right, in theory. . . but I can't imagine it's worth more than a 0.001 in shoulder position, on a good press, after you've consistently annealed.
  10. Chuck R.

    Chuck R. Member

    Jan 23, 2005
    Leavenworth, KS
  11. Metal God

    Metal God Member

    Sep 12, 2015
    I Love them !!!

    Although I'm not going to say what's been said here is wrong . I do believe it has not fully explained the use/purpose of the competition shell holders .

    As some have stated often when sizing your cases and you want minimal shoulder bump from your fire formed case . The standard shell holder deck height will size the case ( bump the shoulder back ) to much if the die and shell holder are making contact at the top of the stroke . The quick and simplest way to solve this issue is to back the die out what ever amount is needed to get the bump you want .

    Nothing new so far , However all presses have what's called flex , deflection or give . A lot of the time that flex or deflection is in the linkage of the arm and ram but also can be in the press body as well . namely in open faced presses like the "c" type or the Redding T-7 type . Remember there is quite a load being put on the press depending on the case you are trying to size and there is always going to be some give somewhere .


    Here is a Hornady "O" type press with the ram fully raised and a empty 308 die and standard shell holder just barely touching . Note : there is no gap or daylight seen between the die and shell holder .


    Now here is that same set up ( die has not been adjusted ) sizing a case . Notice now there is a gap between the die and shell holder .

    This is do to the heavy load now being exerted on to the press while actually sizing a case . Now a 223 will likely put less a load on the press then a 300win mag but there is always a load your press must hold regardless of the size of case being sized . The type of case lube can effect this as well , the slicker it is the less the load should be .

    So why am I bringing all that up ? To get really consistently sized cases ( head to datum ) you need to remove all that flex/deflection while sizing a case . The best way I've found is to be sure the die and shell holder make firm contact through the top of the ram stroke . This gives you a ( lack of a better term ) mechanical zero because the space in which the case can fit is fixed because the die and shell holder are in contact with one another .

    Wait , but we already know that if the die and standard shell holder make firm contact the case/shoulder will likely be bumped much more then you want ??? This is where the competition shell holders come into play and is what they are designed for . By using the comp shell holders you can still have the die and shell holder making firm contact at the top of the stroke with one another all while being able to size your cases from head to datum longer in .002 increments all the way up to +.010 longer then you can with a standard shell holder .

    That's the general points to the comp shell holders . There's more we can talk about but that's the important bit as it pertains to the OP .

    Hope I wrote that in a way that was understandable and it helped
    Last edited: Jun 3, 2019
  12. Chuck R.

    Chuck R. Member

    Jan 23, 2005
    Leavenworth, KS
    Metal God,

    EXCELLENT explanation!
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