Powder Charge Variations?

Powder Charge Variations?

This is a discussion on Powder Charge Variations? within the Reloading forums, part of the Defensive Ammunition & Ballistics category; Well, we had the thread on OAL variance, so now I have a related question---what's a typical, or at least acceptable, variation in powder charge? ...

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Thread: Powder Charge Variations?

  1. #1
    Distinguished Member Array kazzaerexys's Avatar
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    Powder Charge Variations?

    Well, we had the thread on OAL variance, so now I have a related question---what's a typical, or at least acceptable, variation in powder charge?

    I have a Dillon RL-550B and am using Hogdon Titegroup to load .45 ACP. When I change powder settings, I throw 4 or 5 charges before I start measuring, and I see variations between throws of +/-0.1gr. Now a tenth of a grain may not seem like a lot, but when the entire published loading range for that powder is 4.4--4.8, well, it starts to look like a lot of variation.

    When I ran the chrono on five rounds randomly selected out of my last batch, I had an average around 700fps but with min and max off that by about 40fps in either direction.

    What sort of consistency do other folks see in their powder charges...?
    “What is a moderate interpretation of [the Constitution]? Halfway between what it says and [...] what you want it to say?” —Justice Antonin Scalia

    SIG: P220R SS Elite SAO, P220R SAO, P220R Carry, P226R Navy, P226, P239/.40S&W, P2022/.40S&W; GSR 5", P6.


  2. #2
    Distinguished Member Array Reborn's Avatar
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    I have found that my Dillon is a little weird with certain powders. I use Accurate Arms powered when reloading all my pistol ammo. I have pretty much no problems with my powder weight drifting.
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  3. #3
    Member Array spooter66's Avatar
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    I see some variation on certain powders, some are worst then others. I'm currently using up some IMR 800X for my 45 ACP rounds and it doesn't meter very well. I usually see a +/- of .1 grn. I'm not too concerned about it, it has a load range of 6.4 to 7.9 and I load at 6.5. If you have a small load range it could have more of an effect on velocity and accuracy (and safety). If the inconsistant powder throws concern you try a different powder with a wider load range. It will be a little more forgiving of the variations and will give you more room to experiment with the powder loads to find the charge that works best for you.
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    VIP Member Array cvhoss's Avatar
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    While some powders will measure very accurately, most will give some degree of fluctuation. 1/10 grain is an acceptable variation assuming you are not at absolute maximum charge. Most digital scales only read to tenths so with a digital you need to remember that you are probably seeing a much smaller variation. If a charge were weighing 5.54 it would read as 5.5. An increase of only 2/100 would put the actual weight at 5.56 but would read at 5.6. If you are loading at absolute maximum charge (something I would not recommend on any progressive press) you should be weighing each charge.

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    Member Array showmebob's Avatar
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    Using my Hornady Lnl ap with Unique powder I get +.1 variance on average. The most ever was +.2 and that was just one time.

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    Member Array alfack's Avatar
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    My experience has been that certain powders, like AA#2, will throw very accurately, while others, like VV N340, will not. With the AA, I will not even feel the need to weigh charges, once I get it set right. With the other extruded type powders, I feel the need to check often.

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    Distinguished Member Array kazzaerexys's Avatar
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    Hoss, I throw ten charges to get a reading on the load for just that reason. So I know that my 10x4.7gr ends up being 46.5--47.5. Again, I realize that a range of a tenth of a grain isn't a lot in absolute terms, it's just that I am loading a cartridge that has a usable range of only .4gr in this powder; I am shooting for 750fps out of a 5" barrel for IDPA power, and I would like to avoid getting hosed at the match I have in just over a week if I fail the chrono test because I give them rounds with too much variance...
    “What is a moderate interpretation of [the Constitution]? Halfway between what it says and [...] what you want it to say?” —Justice Antonin Scalia

    SIG: P220R SS Elite SAO, P220R SAO, P220R Carry, P226R Navy, P226, P239/.40S&W, P2022/.40S&W; GSR 5", P6.

  8. #8
    Distinguished Member Array kazzaerexys's Avatar
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    Well, as I just posted in one of my other reloading threads, I did 25 rounds last night, one by one, to get as accurate as possible on the powder charges for chrono testing.

    I think my biggest issue may be "stacking". If I am using the press to do one shell at a time—as I was last night and as I do as I am dialing in adjustments—there is extra powder buildup in the hopper from the unthrown powder (when stage 2 is empty), and the next load definitely tends to be at least a tenth higher than average, sometimes even two-tenths. Once I throw that heavy charge, the next one tends towards being light be about a tenth, and then things seem to settle in.

    By the end of my loading last night, when I put a new shell in I'd de-prime and prime, throw two charges and dump them back in the tube, weigh the empty brass and primer, then throw a third charge. Done like that, that third charge would almost always end up weighing in right where I wanted it (within the limits of the scale, of course).

    A little tedious to have to throw three times the powder that I keep, but I guess when I am truly running progressive and dumping the powder on every stroke that I am getting a more consistent powder load than it seems when I am fiddling around with settings.
    “What is a moderate interpretation of [the Constitution]? Halfway between what it says and [...] what you want it to say?” —Justice Antonin Scalia

    SIG: P220R SS Elite SAO, P220R SAO, P220R Carry, P226R Navy, P226, P239/.40S&W, P2022/.40S&W; GSR 5", P6.

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