7mmAM Case Forming

Discussion in 'Reloading' started by TMR, Nov 5, 2006.

  1. TMR

    TMR Well-Known Member

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    Does anyone have some pictures of what the cases should look like for each step of the neck down process? I was going to start necking down some Lapua brass, but did not want to ruin the brass. Kirby said to maintain the Lapua shoulder angle, but I would like to see what each step looks like. I probably won't be seeing the rifle for a few more months....been raining ever since I got back from Montana, so I am trying to find things to do. /ubbthreads/images/graemlins/grin.gif
     
  2. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    TMR,

    I would recommend that if you want to start forming cases thats fine but I would only neck them down so that the neck diameter is around 0.330" or so and stop there until you get the rifle.

    The reason is because when you do the final neck sizing to bring the case neck down to 7mm you will want the rifle there so that you can check the cases in your chamber to be sure you have the slight crush fit that you will want to control any case head stretching upon fireforming.

    If you size them all the way down now it is possible that you will not have this crush fit to control the case during forming.

    Maintain the shoulder angle down to that point best you can and then I would hold up for the rifle to get there.

    Good Shooting!!

    Kirby Allen(50)
     

  3. TMR

    TMR Well-Known Member

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    Kirby,
    I thought that is what you told me before......So if I get this right (I practiced on 1 case) I will need to move the bushing up a little on each step to keep the shoulder angle correct? The neck length will shrink a little, but the shoulder angle stays the same. I might wait until I come over and have you show me, but since this is day 6 of rain (8" so far) I am beginning to get a little cabin fever. I can only reload so many shells and polish so much on my motorcycle. /ubbthreads/images/graemlins/grin.gif
     
  4. ss7mm

    ss7mm Writers Guild

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    TMR:

    I understand your cabin fever and the urge to get some cases formed. I went through this phase while waiting for my gun also. I was going to form some ahead of time, except for the last stage but I ended up waiting until I had the gun and it worked out fine. It really doesn't take that much time to neck down a couple hundred cases and having the gun/chamber there is the best way to get the slight crush fit Kirby is talking about.

    Just try to maintain the original shoulder angle and you're right about moving the die/bushing, otherwise the angle would get off. The important part is the final fit. After you touch off the fire form load all's well with the world and you have a nice sexy looking case to start working with.

    This is a picture of a standard 338 Lapua case on the left, then second is a sample case that is ready for bullet seating, third is a fire form load and on the right is a fire formed case that has been loaded for full power testing. I've only done a couple hundred so far but I've never lost a case. I'll probably do 200-300 more this spring. Sorry, but I don't have pictures of each stage.
    [​IMG]
     
  5. James Jones

    James Jones Well-Known Member

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    Holy cow ss7mm what is that your loading in those cases , looks like an arrow!!
     
  6. TMR

    TMR Well-Known Member

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    Thanks Dick,

    Your sample is pretty much identical to what I ended up with in my experiment. I might wait until the rifle is finished, as you are correct, it doesn't take that long. I have a few hundred rounds of Lapua brass sitting here on the floor. On a separate note....how was your elk season? I talked with some guys that hunt around Wenas, and they said it was pretty tough this year.

    That is a "sexy looking" case.....looks awesome with the 200 gr bullet. /ubbthreads/images/graemlins/grin.gif
     
  7. ss7mm

    ss7mm Writers Guild

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    JDJones:

    Those are some of the "little" 200 grain Wildcat ULD RBBT bullets. And there's a whole lot of bullet down in the neck also. /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/smile.gif /ubbthreads/images/graemlins/grin.gif Little Canadian guided missles. /ubbthreads/images/graemlins/smile.gif
     
  8. ss7mm

    ss7mm Writers Guild

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    TMR:

    Elk season stunk big time. /ubbthreads/images/graemlins/mad.gif /ubbthreads/images/graemlins/mad.gif I saw 29 cows and calves and no bulls of any kind. Kinda similar to what most people I talked to experienced. I didn't even hunt deer in Washington this year.

    As things stand now I'll not be hunting in Washington next year. Plans are for all out of state hunts next year. You kinda get spoiled when you hunt in another state that's managed right and has great game populations. Then you come home and seeing a coyote is the highlight of your trip. /ubbthreads/images/graemlins/mad.gif
     
  9. TMR

    TMR Well-Known Member

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    [ QUOTE ]
    TMR:

    Elk season stunk big time. /ubbthreads/images/graemlins/mad.gif /ubbthreads/images/graemlins/mad.gif I saw 29 cows and calves and no bulls of any kind. Kinda similar to what most people I talked to experienced. I didn't even hunt deer in Washington this year.

    As things stand now I'll not be hunting in Washington next year. Plans are for all out of state hunts next year. You kinda get spoiled when you hunt in another state that's managed right and has great game populations. Then you come home and seeing a coyote is the highlight of your trip. /ubbthreads/images/graemlins/mad.gif

    [/ QUOTE ]

    Dick,
    I could not have said it better myself....I don't plan on hunting here next year either. Hopefully I will get drawn for Montana next year, I did not get drawn this year. Then off to Idaho from there. We had talked about putting in for Wyoming Antelope tags also, but not sure yet. We hunted the both the East and West side of the state for deer and only saw 3 does the whole time. Spend less than a week in Montana and saw hundreds of deer and antelope. Thanks for the info on the case forming. Maybe when the rifle is finished, I will get in touch with you for some shooting.