Factors Affecting Accuracy

Discussion in 'Reloading' started by Greg5611, Jan 16, 2018.

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  1. Greg5611

    Greg5611

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    Been reloading 9mm and 40 S&W for a couple of years and compete in USPSA. I'm trying to work up "accurate" loads i.e. group size <2" at 25 yards. My question involves trying to determine the most critical variables that contribute to increased accuracy or, lose of accuracy. Is there a ranking of variables to manage and/or nail down first to get the most accuracy from a 9mm or 40 S&W handgun load? Is there a force ranking of:
    OAL
    Bullet type (FMJ, JHP, Coated, etc.)
    Bullet profile (RN, FP)
    Velocity
    Powder (fast vs. slow)
    Other?

    I've been playing with Titegroup, Win 231, HS-6 for 9mm and VV n320 for my STI 40.
    I'm reasonably happy with 5.0 gr of VVn320 with an OAL of 1.65 for my STI (Major PF); however, I'm struggling to get a good accurate load for either my Glock 19 or my Sig P229. Any help with how you guys do load development would be appreciated.
     
  2. jmorris

    jmorris

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    1. Person
    2. Firearm
    3. Sighting system
    4. Ammunition

    Unless the ammunition is crap then it can move up, as long as the other variables are equal.

    As far as ammunition, the bullet would be #1. Unless the velocity was insufficient to get it out of the barrel and to the target.

    Lots of variables and what works (or makes the most difference) in one case, might not make any perceived difference in another.

    If it were that cut and dry, there wouldn’t be a “reloading forum”, rather just a “data page”.
     
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  3. Taterhead

    Taterhead

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    At the tippy top of the list, for me, is bullet type and bullet diameter. E.g. Jacketed bullets with square, well defined heels that are full diameter or cast bullets sized right.

    EDIT: regarding your Glock, be sure that your bullets aren't at all undersized. Accuracy goes to crap if my bullets aren't full diameter. Many bullets are 5/10000 to 1/1000 undersized. That little bit makes all the difference. Plated could go 1/1000 over nominal diameter: .356" in the G19.
     
    Last edited: Jan 16, 2018
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  4. andy16

    andy16

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    great question!
     
  5. fredj338

    fredj338

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    Assuming good shooter, good gun, then bullet is the priority for accurare ammo. No shooter or gun can make a poor bullet shoot well.
     
  6. andy16

    andy16

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    in your experience, are berry's plated bullets good enough? admittedly, i blame myself more than my reloads for inconsistency, so i'm happy enough with the berry's price (given the big box sporting good stores will price match the web--i've paid as little as $55/1k!) and accuracy. what's the step up from berry's? does one go FMJ or some hollow point (or base) variation? or should i just start moving to a heavier bullet?
     
  7. jmorris

    jmorris

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    For what?

    I have won lots and lots of matches over the years with them but Berry’s bullet are not the most accurate out of any firearm I own and can be real bad out of some of them.
     
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  8. WeeWilly

    WeeWilly

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    In my experience, plated are the least desirable bullet to load for accuracy. I don't know enough about the manufacturing processes involved in each type of bullet to tell you why, I just only know my own experience.

    Watching friends who are bullseye shooters, who also happen to make their own lead bullets, nothing I can buy matches this process. I have one friend who produces his own lead bullets that are the most accurate I have ever seen in his guns. They are extremely high quality bullets.

    For me personally, in 9mm and 40S&W, I have never bought commercially produced lead handgun bullets that were as accurate as Hornaday XTP/HAP jacketed. The Hornaday bullets have always shot the best from my 9's and 40's. Just below Hornaday, I would place Montana Gold, Precison Delta and Zero. In recent years, I have bought largely Precision Delta jacketed for my action pistol style loads.
     
  9. crockett

    crockett

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    The priority in my book is:

    1.) Firearm incl sights (without a proper tool it doesn't matter how good the shooter is)
    2.) Shooter
    3.) Ammo
    - Consistency of batch (same quality cases, OAL, primer seating depth, bullet weight, etc)
    - Bullet type
    - Charge weight

    My most accurate round is a .32 S&W Long, 3.4gr Bullseye, 100gr Wadcutter, out of a Ruger GP100.
     
  10. jmorris

    jmorris

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    No kids yet?
     
  11. Taft93730

    Taft93730

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    If the bullet is undersized, the rifling won’t be effective?
     
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  12. Greg5611

    Greg5611

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    Thanks, I’m moving away from plated bullets and have been loading Precision Delta 124 gr JHP and these work great in my JP 9mm PCC rifle with HS-6 (1” groups at 50 yds); however, in my Glock 19 and Sig, the PD JHP doesn’t perform well with loads I’ve worked up using Titegroup Win 231 or HS6. The 124 grain FMJ performs somewhat better but my group size is still way too large to be acceptable to me. It seems I have to be doing something wrong or, not paying enough attention to some detail. That said, I don’t clean primer pockets or sort my brass case stamps for 9mm (I do fo 40’s) and I know this should help my group sizes but I’m reasonably sure I’m missing something else. Thanks everyone for your input!
     
  13. jmorris

    jmorris

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    In 9mm my most accurate loads use JHP’s.
     
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  14. Greg5611

    Greg5611

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    Do yo
    u mind sharing your recipie? Powder, charge weight, OAL, bullet weight?
     
  15. Hoser

    Hoser Ninja

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    The way that JHPs are manufactured lends them to being more accurate. Very rarely will you see someone who is shooting excellent groups shooting anything other than a JHP.
     
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  16. jmorris

    jmorris

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    A lot of them are over max data but this is a pretty good one.

    5.7 grains of Universal Clays with a Winchester 115gn JHP @ 1.100”

    This is 10 rounds of it at 100 yards.

    274C7E02-EA92-41FE-AE97-33F54AE3F85E.jpeg

    Contrast that with another [email protected] yds of the 9mm minor load I have won the most matches with...

    15A60331-6AFF-439F-A112-F9B38F4C293C.jpeg

    ...and you will see why it’s good enough for action pistol games but a poor load for anything that demands some sort of accuracy at 100 yards.
     
  17. Boogieman

    Boogieman

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    I have to agree. 20 years ago I talk to Veral Smith (LBT) about some molds for 10mm and 44 mag hunting loads. He had me make chamber casts (Delta Elite with Bar-Sto barrel, Glock 20 and Ruger Super Redhawk) of the three guns. I have yet to find any commercial bullet that even comes close to the accuracy of these three very heavy, gas checked, wide flat nose projectiles.
     
  18. WeeWilly

    WeeWilly

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    In my experience, doing the types of things that result in big gains in something like bench rest rifle at loner ranges, yields little in handgun accuracy at say 25 or even 50 yds. Things like the ES of the velocity numbers (within reason) just don't seem to count as much.

    I suspect much has to do with the fact that you aren't dealing with barrel vibration frequencies (much less as the barrel gets shorter (relatively stiffer), bullet drop variation due to velocity changes, etc.

    Once you get a quality bullet that works in your barrel, and get a powder that burns relatively efficiently at the target velocities you want to achieve, the rest is pretty much gun and shooter. At least, that is my experience, but this coming from a guy that wasn't a Bullseye shooting kind of guy.
     
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  19. WeeWilly

    WeeWilly

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    I think to some degree, much like reloading to get something better than you can buy commercially for your specific gun and application, I view custom bullet molds and casting in the same way. It seems to hold the potential to "up the game" when it comes to performance that just isn't available to us store bought crowd.
     
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  20. fredj338

    fredj338

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    IMO, no plated bullet will be as accurate as a jacketed or even good cast. If you want best bullets, then be prepared to pay for them. The XTP & Sierra JHP are some of the most accurate bullets I have ever shot in a handgun, regardless of caliber. A slightly cheaper bullet would be the MontanaGold. Generally a JHP will be the most accurate. Theory is the weight is at the rear & the more uniform solid base.
     
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