primer seating question

Discussion in 'Reloading' started by dmax1800, Feb 1, 2014.

  1. dmax1800

    dmax1800 Well-Known Member

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    I'm loading some 22-250 with new Norma brass and Remington LR primers. I used a Sinclair primer pocket uniformer before loading the brass. I checked the pocket depths after running the uniformer on them and they were just above SAAMI min specs.
    Now when I seat some of the primers with a Hornady hand primer until I feel it stop, ie primer is at the bottom of the pocket, some stick out past the end of the case. I have to give them just a little more pressure to get them just below the case (.001"). When I do this, apparently it puts a little bulge in the end of the case. When I measure some of the loaded rounds from the end of the case to the ogive with a bullet comparator on a caliper, I get more than a dummy round with no primer installed.
    I'm loading these for a bolt rifle, not an automatic.

    So my question is: A) is it better to leave the primer stick a little past the end of the case and not cause any bulging or B) put a little more pressure on the primer to get it seated just below the case and cause some bulging?
     

  2. Barrelnut

    Barrelnut Well-Known Member

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    The top of the primer should be below the head of the case, no matter auto or not. Usually, after using a primer pocket uniformer, they are a couple thou lower than without a using a uniformer.

    What is bulging after seating further in? The primer itself? Some primers and brass can have a tight fit and if the primer is a softer one, the top of it will flatten a little. No big deal.

    Also, Hornady primer seaters come with two different trays, a green and a back one. The green is used with RCBS shell holders and the black is for Hornady shell holders. It can make a difference in how deep the primers seat.

    Can you post a pic?
     

  3. Bullet bumper

    Bullet bumper Well-Known Member

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    If you have uniformed the pocket depth then the seating should be fairly easy and not above the base of the case . My guess is you have not cleaned the uniformer cutting flutes enough and it is not getting right down.
    It will stop cutting when it loads up with chips . So clean it off with a tooth brush and do it again . I think it will cut down some more . Keep doing that until it will not cut anymore at all. I like my primers level or just below the head and seated all the way home .
    If you are bulging the head any , you are using too much force .
    A bad sloppy shell holder could be causing the rim to be poorly supported .
    Norma brass is usually good quality .
     
  4. dmax1800

    dmax1800 Well-Known Member

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    The primers are a tight fit in the new brass. The case head is apparently bulging, not the primer. The primer doesn't stick past the end of the case head. On some cases when I seat the bullet, the case head to ogive is longer than on a case with no primer.

    I don't think I could get a picture of a primer that is .001 or .002 above the case head. I also don't think I could get a picture of a small bulge resulting in .005 longer case length.
    I am using the green tray with an RCBS shell holder.

    The pocket uniformer is clean. I clean it every time I use it.
    A bad sloppy shell holder is a thought. I have another one I'll try. Thanks.
     
  5. MagnumManiac

    MagnumManiac Well-Known Member

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    I cannot see how the case head can 'bulge' from seating a primer, it's not possible as far as I am aware. I believe the primer is high and giving you a false reading.
    All primers are designed to not only bottom out in the primer pocket, but also to push the anvil into the cup until it is also flush with the bottom of the cup, this gives the priming mix a slight pre ignition squish and sets up the primer to take the full hit from the firing pin, if it isn't flush, some of the firing pin energy is absorbed by the primer being seated further into the cup, it is necessary for the primer to be seated .003"-.005" below flush for the above factors to be present.
    Some primer and case combo's are just harder to seat, if the primer is still high you will have to reseat it until it is below flush.
    I have this problem with Norma cases and Federal primers, but Winchester primers don't seat as hard and bottom out without having to use excessive force.

    Cheers.
    gun)
     
  6. Bullet bumper

    Bullet bumper Well-Known Member

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    You have to clean the chips several times as you use it otherwise it does not cut all the way down . Is the uniformer a fixed depth type or adjustable depth type ? Some times heavily stamped case heads can have a rough edge to the lettering that stops the uniformer cutting all the way down to the correct level.
    Rub the case heads lightly on a flat sharpening stone just to see what sticks up . I still think you are not persisting long enough with the cutter .
    Make sure the cutter is cleaning out right to the corner of the pocket .
     
  7. AZShooter

    AZShooter Well-Known Member

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    You are not the first person mentioning primer seating issues with Norma brass. I have encountered this too.

    I use a variable speed drill adjusted for low RPM and make two or three passes cleaning chips with each pass. On some cases the sides were so tight I couldn't get the pocket uniformer to cut easily. A tiny bit of water placed on the cutter's outside lubes enough to get the pocket cut deep enough.

    I found that my old uniformer didn't do the job and purchased a new RCBS uniformer which works much better. Maybe you need to switch cutters.
     
  8. dmax1800

    dmax1800 Well-Known Member

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    The uniformer is a fixed depth type. I'll try rubbing the case head to see exactly what is high. But I think it is interesting that measuring case head to ogive on a dummy round (ie no primer) is consistently the same and sometimes measuring case head to ogive on a live round with the primer just below flush is longer than without a primer.

    I also use a drill with the uniformer. But when I measure the pockets, they are slightly deeper than the SAAMI minimum spec. I may have had the same problem with some Norma 300 win mag brass and just didn't realize I did have the problem. I haven't had the problem with Norma 270 win brass. I checked RCBS website and they only have uniformers for their trim mate and I don't have a trim mate. I thought that Sinclair stuff was good stuff.
     
  9. AZShooter

    AZShooter Well-Known Member

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    I just chuck up the RCBS cutter in the drill even though the threads are squeezed in the jaws. I suppose a few nuts threaded on that shaft would save the threads.

    The trim mate primer pocket uniformer also fits on one of those RCBS green handles.

    -----------------------


    Have to wonder if a deeper seated primer would make a difference if all were the same depth?
     
  10. valleyloader

    valleyloader Well-Known Member

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    Put a straight edge against the head to see what exactly is higher after the primer is seated. If you are certain it is not the primer itself, there is a possibility of bending the rim of the case if using too much force to seat the primer. If you have ever stuck a case in a die then you will realize what I am describing. Just a suggestion to try, it seems like you have already eliminated a lot of possibilities.
     
  11. dmax1800

    dmax1800 Well-Known Member

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    That is exactly the problem. I had been running the drill for several revolutions and calling it good. On the few pockets that I measured after running the uniformer, they were probably deep enough. I rechecked a few and found some at .130 and some at .126. After running the uniformer and cleaning it several times, the .126 pockets came up to .130. When I seated the primers in the pockets with .130, I was able to get them recessed by .001 to .002 and the case did not stretch: they stayed at 1.900, which was my trim length.

    I also tried a Lee and RCBS shell holder. The Lee is apparently a little sloppy and does not give the support of the RCBS. It was easier to get the primer seated with the RCBS than with the Lee.

    Side note. SAAMI spec for LR is .125 min and .132 max. At the minimum it would be hard to seat the primer flush or slightly recessed without starting to crush the primer.

    Thanks guys for all your input. I don't think I could have figured this out without your help.
     
    Last edited: Feb 2, 2014
  12. Trickymissfit

    Trickymissfit Well-Known Member

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    interesting issue with the chips clogging in the cutter relief. I use a couple K&M's in an electric screw driver, and have never saw this issue. Pockets come in at .130" everytime with one cut. Are you using some sort of a lube when cutting the brass? I don't.
    gary
     
  13. dmax1800

    dmax1800 Well-Known Member

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    No, I'm not using any kind of lube, just a Sinclair uniformer.
     
  14. Bullet bumper

    Bullet bumper Well-Known Member

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    The Sinclair cutter is not an aggressive angled cutter so it is slow , but also that makes it less likely to go off axis and produces a smooth surface . There is not a lot of chip room anyway and they tend to feed back under
    the cutting edges and make the teeth slide instead of cutting. If extra force is used it will eventually cut through but it's not wise to do that as surface finish will suffer and the cutter will get blunt much quicker .
    No big issue once you know that.