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OAL Measuring ?

Discussion in 'Reloading' started by Tomcat10, Feb 10, 2017.

  1. A6Gator

    A6Gator

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    So essentially you're loading to 1.123 +/- .004. Even when sorting brass by head stamp, I get variations in case length, especially if it's range brass. If you trimmed all your pistol brass to the same length (.845), you'd probably shrink it a bit more, but I don't know anybody that does that. I figure as long as it functions in my pistol (the case gauge is my friend) and is accurate enough to shoot in USPSA, IDPA, Steel Challenge or 3 Gun, I'm good. If you're a bullseye shooter, it might be worth the extra effort.
     
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  2. fredj338

    fredj338

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    Some BE shooter would have to prove this to me using a Ransom rest. Hmm, sine I just got one, maybe I will run that test.:supergrin:
     
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  3. A6Gator

    A6Gator

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    I think that'd be a great experiment.

    My thinking was, like the benchrest guys, they try to take out all the variables (sort cases by length, case run out, weigh/sort their bullets, primer hole consistency, etc.,) so their ammo is as consistent as they can get it. If you sort by headstamp, trim to the same length, I would think, given an accurate powder drop, that it would be more consistent. Any bullseye guys out there?

    It's not clear to me, even if it is more accurate, if it's worth the extra time involved. For practical competitive shooting, how much is "good enough?"
     
  4. halfmoonclip

    halfmoonclip

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    When I was first reloading, I didn't have a decent dial caliper; only a set of mechanical 'slide rule' verniers. As a result, I kept a dummy 'check load', and used the vernier to check against it, and also to set the bullet seating punch. In some ways, it was probably more accurate than my nice dial unit.
    A weird reason for OAL variance; a buddy was having extreme variance (you could pick them out bullet down in the box). Anyway, his resizing die wasn't resizing enough , and the bullets in some cases were falling in to the case. This could cause pressure issues too. In any case, he has new dies on order.
    Moon
     
  5. judgecrater

    judgecrater

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    Exactly. Back when I was loading bullets with waxy lube, it would build up in the seating die. I now only use jacketed or HiTek coated lead. Better for a number of reasons.
     
  6. halfmoonclip

    halfmoonclip

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    Our late range officer used to cast for all of us with lead he retrieved from the range water tank.
    Not unreasonably priced FMJs, Glock rifling and lead issues have kept me away from lead anymore.
    Crud in the seating plug can be an issue.
    Moon
     
  7. jdavionic

    jdavionic NRA Member

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    Brown & Sharp dial caliper
     
  8. NewBest45

    NewBest45

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    I seat bullets at one station and crimp at the next station. I have found that the semi wad cutter seating stem gives the best consistency in OAL. If you can use the SWC stem, with your bullets started as close to straight in the case as you can, then the bullets should be straight in the case.
     
  9. halfmoonclip

    halfmoonclip

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    Best', I've experimented with using flat seating plugs, and even turned one from a bolt, and your suggestion works well with some bullets. The concave seating plugs do have a self centering nature, but any variation in bullet/plug shape can cause variation.
    Moon
     
  10. NewBest45

    NewBest45

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    At some point the seater plug is going to grab the bullet and ram it into the case until it stops. My best results start with a bullet that is straight as possible in the case before it is engaged by the seater die. The shape of the plug has to work with the bullet that you plan to use or you just smash things up.
     
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  11. refugeepj

    refugeepj

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    + or - can be different if one round is seated with a slightly different amount of force.
    there will always be a deviation. no such thing as perfection.
    i am finishing another 1,000 PFP 124 Xtreme run, and my deviation has been + or - .003. minimum is never compromised. most are within .001, but a few are a bit more.
    measure some factory rounds and you will note a large variation.
    one of the reasons for reloading is more consistent rounds.
     
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  12. unclebob

    unclebob

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    The best thing I did was go to Redding competition bullet seating die.
     
  13. halfmoonclip

    halfmoonclip

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    Bob, you can tell us a little more about that? Is that the micrometer one?
    Refugeep, I believe you are exactly correct. Running the press smoothly even affects powder drop, and there is some slop/flex in the press itself that will also be affected.
    Moon
     
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  14. unclebob

    unclebob

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    Yep it's the micrometer one.
    Yep its the micro adjustment die. All you have to do is keep track of what the settings are. And you can go from whatever different weight shape bullet you want. As long as it's the same caliber. And then go right back to what you load the most of. The easy way is to adjust the die using a Allen key to set for the bullet shape and size you shoot the most to zero. Then adjust by turning the dial to what other bullet shape or size you want. Turn it back to zero and you are right back to what you load the most of. To me it is well worth the price.
     
  15. halfmoonclip

    halfmoonclip

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    I really hate messing with the seating plug; once it is set for a standard load (my 9mm fmj, for instance), I leave it the hell alone. There always seems to be some runout that is compressed by seating the bullets. Bob, does your micrometer die have this issue, and how pricey are they?
    Thnx,
    Moon
     
  16. unclebob

    unclebob

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    They run about 86.00 for handguns. Just like all dies, make sure everything is still tight every once in awhile. Plus don’t use lead bullets with grease. I really can’t think of anything negative about the die. Other than it would be nice they they had a set screw where the micro adjustment would not loosen up.
     
  17. halfmoonclip

    halfmoonclip

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    Thankee, Bob. The $90 talked me out of it, especially with the caveat that it lacks a set screw.
    I crank down the locknut, and the pressure of loading still takes out the slack in the threads. I fudge around 'till the loads are pretty much the right length.
    Moon
     
  18. NewBest45

    NewBest45

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    The Redding competition die is no guarantee that you will not have sizable variation in OAL. The shape of the seater plug has alot to do with it, they will make one for you if you send them some bullets.
     
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  19. cowboy1964

    cowboy1964

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    Digital calibers. I must be lucky, I never see enough variation to even think about worrying about. (LCT press, 9mm, Berrys bullets, random brass)
     
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  20. fredj338

    fredj338

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    I think way too many guys worry about this sort of minutia. Put 0.005" on your calipers & look at it, it is barely visible & means nothing to the accuracy or safety of the load.
     
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