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Powder Charge and Point of Impact

Discussion in 'Band of Glockers' started by doctabako, Jul 17, 2004.


  1. doctabako

    doctabako
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    Excuse me if this sounds like a dumb question.

    In the last competition my loads failed the chrono so I asked my reloader to increase the powder charge of my reloads. I've noticed that increasing the powder charge ( .2 difference) changes the point of impact a tad lower using the same heads.
    I'm guessing that the increased powder charge makes the projectile leave the barrel faster thus lowering the point of impact, as compared to a lower charged slower projectile which leaves the barrel relatively later when the muzzle is on its way up due to recoil. Am I right? or am I imagining things;f
     

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  2. FAlvar

    FAlvar
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    Lighter or faster bullets will impact lower.
     

  3. Eye Cutter

    Eye Cutter
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    docT: what is your reloader's recipe? what powder do you use? with the increased powder charge, have you had the chance to chrono it?
     
  4. mc_oliver

    mc_oliver
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    docT, during my experiments with powder charges, I didn't notice any acuracy changes (but I didn't really bench my gun then). Accuracy only varied when I changed heads (weight and type).

    Maybe it's a timing issue with the increased charge. What's your load btw?
     
  5. doctabako

    doctabako
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    Thanks for the confirmation. Guess I'll now have to raise the elevation a click.

    Doc, original load(by BoyT of True Power) which I used at Varilla was 200 gr LFN(weighed in at 197-198 gr max at Varilla) with 4.1 gr AP-70 , 1.180 COL at 4 degrees. Chrono 829-850. Final PF was 168

    New load has same heads with 4.3 gr of AP-70, 1.180 COL at 7 degrees(what do the degrees mean?) Just got them yesterday, don't have access to a chrono but there's a noticeable difference in the feel( I can track the sights better) and I find that it brings down plates/poppers faster but they print lower by 1 to 2 inches ( at 15 meters) than the former load.

    There was another thing that I changed and I don't know if this has any bearing. Due to the increased charge, I doubled the shock-buffs(maybe this accounts more for the improved feel)but then again I used this set-up with both loads so maybe not.

    Could be a timing issue with the subsequent shots but I also tested it one shot at a time( if that's what you mean) and I do feel that the guns zero changed with the new load(its a feeling that somethings not right even if you aim carefully)) . Then again could just be my aim;f
     
  6. Eye Cutter

    Eye Cutter
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    168 na pala PF. we want your velocity readings to be consistent at 870 fps and above. The 4.3 gr should get you over 170 PF.

    you'll notice that when shooting a more powerful load, to a certain point, it will feel flatter than with a lower charged load, meaning the recoil impulse is easier to control and gives a snappy return to point of aim. you can experiment and change the way the muzzle jump rises by using different bullet head weights. heavier heads will generally have higher muzzle rise than lighter heads.
     
  7. doctabako

    doctabako
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    Thanks Doc. I sure hope it does(go over 170)sayang points when scored minor. :)
    I like the feel of the heavier heads, but will experiment more with lighter heads in the future once I'm assured of the PF of this present load. Buti pa kayo sa PB may chrono. Eliminates the guess work :)