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Ok a quick question, I have noticed that with fine powders, like h110 my powder measure will throw a charge within 1/10th of a grain of what I want. No biggie with my pistols at all. But with a larger stick powder like IMR 4831 it throws a charge within a half a grain. I'm not working with top end loads, is the half a grain variation really that big a deal? My OCD has been making me weigh and trickle a exact load for my gun, but does it really matter????
 

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Depends how much you want to fiddle attaining the "exact" loads.

With 4831, any load within a half grain probably isn't going to make a big deal for general target shooting. If you're loading for the smallest grouping, then it may make enough difference to be barely noticeable out on paper. Proper bench technique adjustments will make a bigger difference.

Being sorta anal on such things, I use the manual powder measures for handgun plinking and the Lyman Gen 6 electronic measure/scale for the rifle cartridges. It will measure .1 grain +- and that small difference doesn't affect my groupings that much. Especially with age, weakening eyesight and body tremors. :)
 

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The metal baffle over the powder has proven effective. They are available. Many make their own.
 

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Perfect, you do the same thing I do, only I use a beam scale for rifle loads. Thanks kdub... I'll stick to being OCD about my rifle loads haha. I've never worried about the pistol loads, like you said within .1 grain won't make a difference, especially with my pistol skills ;)
 

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Late to the party is not unusual for me.
I use IMR-4831 in one particular cartridge/rifle. I have noticed (over several decades) that my Uni-flow gets very consistent as the number of cases charged gets past some figure (say 20 or so +/-). My technique has been to throw/weigh/trickle/adjust Uni-flow until it is spot on for several in a row. Then throw several (like maybe 5) and check weigh one. If I keep the hopper purdy full, and the bushing nut tight, I can run real good. Consistent operation of the handle is a must.

If the bushing lock nut has not been tampered with, returning to consistent throws happens even sooner (assuming same powder lot) next time at the loading bench.

Cheezywan
 

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This due to 4831 being a stick powder. Stick grains can orient and pack in different ways that alter the bulk density of the powder. Below is what different length drop tubes do to it. The longer the tube, the more it bounces around and tries out different packing arrangements. Spherical powders change bulk much less when you do the same thing with them. As a result, they don't need to settle in your hopper before the grain weight per charge gets consistent.



What's interesting about stick powders is their burn rate depends on geometry of flame spread. That mainly effects how their perforations burn, but how the grains arrange themselves also affects flame front spread. That is, if the powder is packed tightly, as in my last image, flame has a harder time spreading between the grains, with the result that it burns like a slower powder. So, when you throw a heavy charge from your measure, it's because the grains have packed more tightly, but because they have packed more tightly, they will tend to burn more slowly, which can compensate for the fact the charge weight is heavier.

I've pulled bullets from Federal Gold Medal Match 308, which is loaded with IMR 4064, and found the charge weights have a span of about 0.4 grains. It still drives tacks.

As Mr. Mortimer says, extra baffles can mitigate differences in packing density. I'll attach my baffle template and instruction set. At some point I updated it and the last page has some templates for specific powder measures, including the Uniflow.
 

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For any who are interested I just used Unclenick's baffle template to modify my uniflow powder measure. It cut the charge weight varibility about in half using IMR 4064. Results at the range yesterday show better groups in two different 30-06 rifles loading by volume than loading by weighing each charge on a beam scale.

I am wondering if adding a second baffle would further help repeatability?

Thanks again Unclenick for setting me on the right path.

Jeff
 

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I have an old Redding powder thrower and with ball it is very consistent but with stick powder it is close but not close enough. I use a 12 inch tube that I made up years ago. When I am using stick powder like 4831 I throw a 1/2 grain light and dribble up. When using slow powders and working close to the top I use this tube.
 

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1/2 gr. of 4831 will not make any difference unless one is truly OCD....:) Also you can't get enough 4831 into most cases to even losen a primer. Ask any bench rest shooter, they never weigh any charges on a scale, they use a particular powder, whatever that may be and just drop a load and shoot it..

I seldom weigh a load, I do look at them under a light, but I never use a powder that does not fill the case enough so that a double charge wouldn't spill over...Im talking rifle loading, not pistol.
 

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4831 short cut goes through my UNIFLO pretty slick. R19 really well. Seldom do any trickling. That measure has been going for 40 years! No complaints!
 

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I've been using a Uniflow for many years.The most consistent throws are with fine, granular powders like H-110, Win 296, Hogdgon LVR, etc. Also, consistent throws occur with the ball powders like Win 231.

On the other hand certain powders like larger flake powders, 700-X for example, as well as extruded rifle powders, throw quite inconsistently. That being, in my experience, some throws being slightly higher and others being slightly lower than the desired amount.

What I've done in cases where I'm using flake or extruded powderrs is to set the change slighly below the desired amount and then use a powder trickler to trickle the powder up to the precise level.

Just a suggestion......

Bayou52
 
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