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Poor accuracy?

Discussion in '10mm Reloading Forum' started by macatex, Feb 3, 2011.

  1. macatex

    macatex

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    I'm having a problem with a load I've been using. I have 180gr Berry's bullets with 8.2 grains of Power Pistol. The problem is the grouping of the bullets in my load is horrible. With factory ammo I can keep a 2" group at 7 yards fairly easily out of a G29. With my receipe I consistently get 6+" groups. Any thoughts on changes I can make that would help the accuracy of the bullets?
     
  2. MinervaDoe

    MinervaDoe

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    I looked through a half dozen of my manuals and none of them had data for PowerPistol in 10mm.
    Then, I found a load for a 180 grain jacketed bullet in my Hornady manual. When I went to look at their 180 grain lead loads, they did not list Power Pistol. Maybe they felt that it was not a good powder for a lead load.
    Since you are shooting plated bullets, you need to find a published load for a lead bullet and start with that. The soft plating comes closer to lead than jacketed material and I'd bet that your load is too hot.

    I beleive that Alliant has a published Power Pistol 180 grain 10mm load, but again, it is for a jacketed bullet and inappropriate for plated bullets.
    Strangely, they don't put their PowerPistol load online for 180 grain.
    http://www.alliantpowder.com/reloaders/recipedetail.aspx?gtypeid=1&weight=180&shellid=30&bulletid=42
     
    Last edited: Feb 3, 2011

  3. Taterhead

    Taterhead Counting Beans

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    My guess is that if you stepped back to 25 or more yards you'd find keyholing. These projectiles wobble or tumble if not treated appropriately. A few things that helped me to resolve the issue are:

    1) don't push them too fast. I keep mine@ 1100 fps or less.
    2) seat them all the way out to 1.26"
    3) use a generous bell when expanding the case mouth
    4) easy on the crimp. Use just enough to iron out the case mouth expansion.
    5) seat and crimp in separate steps

    Doing all of the above has resolved the accuracy issues that I once had.
     
    Last edited: Feb 4, 2011
  4. macatex

    macatex

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    Thanks guys. I have three fairly recent manuals with load data for Power Pistol and the 10mm. I'm using the starting loads listed so I shouldn't be pushing things too hard. I hope!

    Taterhead: I've done all but #4 on your list. I may be crimping a bit too much. I had to pull a bullet while reloading the last time and it took several whacks of the pullet puller onto a concrete floor to get the bullet out. I'll work on that see what happens.
     
    Last edited: Feb 6, 2011
  5. Taterhead

    Taterhead Counting Beans

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    Keep in mind that if you are using load data for jacketed bullets you need to reduce charges by 10%.

    Some Alliant data I have lists a max charge of 8.7 grains for a 180 gain jacketed bullet. That would imply a max of 7.8 grains for the plated bullet. The listed velocity is 1240. I don't know how that would translate to a plated bullet from a shorter barrel, but you may be pushing them a bit.

    Hornady lists a max charge of 8.4 grains. Again, adjusting for plated bullets digests a max charge of 7.6 grains.

    I'd be inclined to reduce to about 7 grains and work up until you find a charge that runs a little better.
     
    Last edited: Feb 7, 2011
  6. lunker

    lunker

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    I only use Berry's for plinking loads and in 45ACP. They shouldn't be run too fast. It is pretty easy to pierce the plating with an incorrect crimp. If that happens, your accuracy is bound to be off.
     
  7. RB98SS

    RB98SS

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    I feel your pain. I've been struggling with a similar load, 8.0gns of Power Pistol and a Berry's 180HP. Can't even hit the 6" target at 30ft. Honest. Now I know I'm not a great shot but I can put every shot in the 6" target at that range with other loads. Something about that combo that just doesn't work in my stock 20sf.

    I 'm leaning towards reserving PP for 357sig and not using it for the 10.
     
  8. texas 48

    texas 48 Gold Member

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    I have get results with PP with 165 155 and 135 gr Bullets. With 165 gr Golden Sabers using 10.0 gr got 1395ft/sec 11.5 SD 715ft/lbs energy. Good accuracy. May not be a good combo for 180 gr bullets.
     
  9. RB98SS

    RB98SS

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    Interesting. I have a bunch of Hornady 155's that I have not loaded at all yet but may have to give PP another try with them. Care to share your 155 load?
     
  10. texas 48

    texas 48 Gold Member

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    G20sf 4.6 in OEM barrel
    155gr XTP 1.255 COAL 10.2gr PP CCI350 1330ft/sec avg. SD 9.44 . very accurate load. I think I can get to 10.4 gr 10mm forum others have loaded 155gr up to 10.6gr . started at 10.0gr since it was max load for 165gr. Good luck work up slowly. I think the 165gr @ 10.0gr is a sweet spot in my 10mm's
     
  11. _The_Shadow

    _The_Shadow Ret. Fireman

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    Macatex, It has to be that the thinly plated bullets are being driven too fast, Glock barrels have a twist rate of 1:9.84" and spin up the bullets a little faster than the conventional barrels at 1:16". Some people have actually found slivers of plating piercing their targets while driving the plated bullets over 1100 fps. Using 8.0 grains of Power Pistol behind a 200XTP in my Glock 29 gives 1135 fps so yours are a tad to fast.

    Therefore much care is needed to control velocity, loading practices need attention as not to shear the plating while seating(Like Taterhead said generous flair), and taper crimps with a lighter touch as not to cut the plating. Get that under control and you should see much better groups.

    You may want to try about 7.6 grains of Power Pistol with standard Large Pistol primers and your accuracy should be right on. Your velocity should be in the neighborhood of 1090-1100 fps.

    Good luck!
     
  12. kfox

    kfox

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    When I was asking Alliant about 180 grain LFP bullets this is their printed response....
    With Power Pistol, I suggest from 7.4 to 7.9 grs

    With Unique, I suggest from 6 to 6.5 grs.

    Hope this is some help to the OP. If you can't find the information you need ask the powder company they probably do have it..
     
  13. nickE10mm

    nickE10mm F.S.F.O.S.

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    Just saw this thread ...

    I load a 180gr Berry's plated HP to about 1050fps with AA7. 8.x gr of PP sounds like a bit too hot.

    Even with my AA7 Berry's load, I don't get match accuracy... I can shoot about 3" 25y groups at BEST with Berry's.... but can regularly shoot 1.0-1.5" 25y group with a nice XTP load... YMMV, but this has been my experience.

    Plated bullets just aren't as accurate as jacketed or lead bullets, in my experience. Good for random, cheap target practice but nothing serious.
     
  14. Taterhead

    Taterhead Counting Beans

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    A really precise load for 180 grain Berry's has been with 8.9 to 9.3 grains of Blue Dot. That is running at about 1025 to 1050 fps. I can get connected bullet strikes at 15 yards. Things open a bit with other powders and faster velocities. Standard primers. 1.26" COL. Crimp just enough to remove the flair.