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Setting powder charge ?

Discussion in 'Shooting Related Threads' started by Hammer1, Jan 2, 2011.

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  1. Hammer1

    Hammer1 Active Member

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    In metallic rifle and handgun cartridge reloading we commonly accept that the powder charge thrown is plus or minus 0.2 grains of the nominal. So we set the powder measure to throw an average powder charge 0.2 grain lighter so we never exceed the maximum powder charge we want.

    Don't know the common plus or minus for shotshell powder measures (bushings), but does the same principle apply ?

    Should we use a powder bushing that throws a slightly lesser powder charge than the manual book list in order to never go over the maximum powder charge we want ?

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  2. kiwiG

    kiwiG Member

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    Hi, Probably not much use to you, but I reload on a Mec 600 Jnr. Old school slow reloader, but if you rattle it the same each shell you get amazingly accurate results. I reload to within .05 gr and check every 5 shells. Cheers-Graham.
     
  3. Unknown1

    Unknown1 Well-Known Member

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    <blockquote><I>"I reload to within .05 gr and check every 5 shells."</i></blockquote>

    I can see trying to get within .5 gr. if your load isn't bumping the limit and your loader operation is a bit erratic but no powder scale will measure to .05 of a grain.

    I aim for the exact charge weight specified, and consistent loader operation generally brings me in at ±.1 gr on the drops I check. A variation of ±.2 gr. of the target weight is acceptable.

    MK
     
  4. short shucker

    short shucker TS Member

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    I pride myself in having a .1 deviation in my powder charges when reloading shotgun shells. This isn't very hard to do with the right powders and knowing how to run a press. I can do this with either my 266 or 366.

    ss
     
  5. Hammer1

    Hammer1 Active Member

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    With an adjustable powder measure like I use on rifle and handgun cartridge reloading, I check charges ever so often out of concern that the adjustable measure has changed its setting somehow. I have about a dozen Dillon metallic cartridge presses and routinely check their powder charges though have very rarely found a problem.

    With a fixed powder bushing like is in my shotshell press, once I know the plus or minus around the nominal charge and am satisfied with it, and the powder measure is reasonably full... Why would I check every five or ten shells for powder charge amount ?

    Not trying to be argumentative or debating at all.

    Just want to make sure that I understand what I would be looking for if I were to find that the powder level had changed after five or ten rounds.

    Am I looking for a defect or malfunction in the shotshell machine ? Or contamination in the powder measure ?

    Should I be checking the shot volume (weight) every five or ten shells too ?

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  6. TomB

    TomB Member

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    Hammer....I have found that that the first couple of shells when you have just filled the powder tube will be about .5 grain heavy. After that they are pretty consistent to about .1 gr. The vibrations that you impart to the machine are rather consistent so the powder shakes into the sleeve uniformly. All in all, small grained powders, such as PB or 7625 are more consistent than flake powders, such as Red Dot,Promo, or 700X.
     
  7. dverna

    dverna Active Member

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    Hammer1

    I check powder charges every few hundred shells (I load about 450/hr and check every 1/2 hr or so) and it is just me being anal. Bushings are not going to "wander" unless your get some crap in the powder and it lodges in the bushing or drop tube. A variation of +/- .2 gr is typical for most machines.

    Don't go nuts. This is not rifle or pistol loading. We are not loading near max (or shouldn't be anyway). I pick loads that run around 9500 psi for target shells so there is a built in safety factor. I pick a bushing that throws at or slightly under the published recipe. You cannot tell the difference between a 17.0 and 16.7 gr load. I have enough bushings that I can get within .3 gr of a load. If the load is a low pressure load (under 8000 psi), I go with the next higher bushings to get a better burn and better cold weather performance - so if the load called for 17.0 gr I would go somewhere between 17.0 and 17.5.

    It is not rocket science and being anal about powder drops is a waste of effort. We are throwing a few hundred pellets out of a tube. Pressure is affected more from the quality and depth of crimp you use than a .3 gr powder change. Bear in mind I DO NOT substitute wads or primers as some folks will do. Using published recipes will keep you in known pressure ranges.

    I rarely check shot drops. But all my bushings throw slightly under. That also means less pressure. I need to get them adjusted as I am sure those few missing pellets are costing me AA ranking.

    Don Verna
     
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