Another revelation - -

Pete Wass

Pete Wass

Well-known member
Whilst loading some ammo for the up-coming State Long Distance shoot I began to realize, I think, that powder measures aren't at fault for varying weights in powder charges, the powder is! I believe I noticed that there is sort of a random difference in the weight of the powder as it cycles through the measure. This could explain why there are variations which occur at about the same rate and frequency regardless of the brand of the measure.

While I will agree it is nice to have measures that have precice repeatable scale and cavity BUT they do nothing to affect the variability in the weight of the charge which falls into the cavity in the cylinder in all of them. If we accept the load they dispense, we depent on the node we are on to forgive the variability.
 
My experience has been that the random variance in the weight of thrown charges is heavily influenced by measure operation technique, as well as other related factors. To the extent that this is true, I believe that the powder is not the reason for charge weight differences, although it may be partly to blame. I should add that 133 is a challenge to throw to the standards that I would like to maintain. Any thing coarser I throw light and trickle to final weight.

Recently I loaded 50 rounds of .338 Lapua with over 90 grains of Retumbo (300 gr. SMK). I used a RCBS Chargemaster (sp?). It did a supurb job of handling this coarse powder.
 
Francis: I've developed a pretty sophisticated method of sifting power that I call the Bolus Method, or B.M.;) for short.

I open an 8 lb'er. of powder and pour a large Bolus of same into a 1 lb. container....all the way to the top. I then toss the B.R.D. (Bolus Reception Device..1 lb container) into my loading box and head to the match. At the match, I transfer the contents of the B.R.D. into the B.R.D.H.U. (Bolus Reception Device Holding Unit..my powder measure). The final transfer occurs when the powder goes from the B.R.D.H.U. to the B.C.V. (Brass Containment Vessel).

I know it's not as sophisticated as sending spent fuel rods to Yucca Mountain in Nevada..but it's as complex as I can make it. :D

Boyd,

There was some published work about sifting powder to eliminating kernels that were oddly sized. It was in the old Shooters News publication.

You probably remember it....just thought I'd throw it in here in case you had forgotten.

Good shootin'. -Al
 
I've noticed the same thing that the powder seems to vary in density, although I've never gone to the trouble of sifting it to separate various granule sizes. In weighing charges while paying attention to measure operating technique there will be several charges that are right on target, then several that are either light or heavy, then back to the target weight. It would seem that if it was my lousy technique that the charge weights would vary randomly from the target weight to light or heavy charges and back and forth. Bewildering to me.
 
I throw start loads, then bring them up to weight on my scales (I shoot long range). I have a different preset thrower for each of the main loads I use & have noticed that they throw different weight depending on ambient conditions. As you might have guessed, I don't have climate control in my loading room & we get significantly different temperatures & relative humidities day to day & even time of the day. I have always attributed the variation in result to these conditions.
 
After I finish weighing my brass between each target I check to see if the next relay has started shooting yet. If so, then I use a special macaroni strainer to fetch just the small particles for my next set of loads. If the second relay hasn't started, then I know I have time to just use my calipers and select all matching powder grains. ;)
 
I weigh all of them

I set my measure to slightly under the charge I want. I figure after the thousands of rounds I have loaded, tecnique should be not that much of an issue and I do find that , regardless of the measure, the randonness is always there. It's as if certain strata in the column of powder in the bottle weigh differently. For sure the cylinder rotating does not change any.

I think a number of folks have found that the ambient is a great contributor to the randomness but I have found it to exist in all the various conditions I have loaded in.

I have been using a Chargemaster for about three years now. I like the way it re-zeros after each charge is weighed. I re-re-zero it every few cycles but do not think it necessary to do so.
 
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Larry,

Larry Elliott said:
I've noticed the same thing that the powder seems to vary in density, although I've never gone to the trouble of sifting it to separate various granule sizes. In weighing charges while paying attention to measure operating technique there will be several charges that are right on target, then several that are either light or heavy, then back to the target weight. It would seem that if it was my lousy technique that the charge weights would vary randomly from the target weight to light or heavy charges and back and forth. Bewildering to me.
Click to expand...

wouldn't there be a problem sifting stick powders, even short grain ones? The stick can sift through lengthwise if it fits the grid size or on end. If a stick goes through end wise it still could be much longer than some that go through lengthwise. It seems sifting stick powder would be a bit more of a challenge than spherical ones?
 
Consistency....

When loading for live varmint rifles before the season I load 100-200rds. at a time for each rifle. An old shooter once told me, "...try a "ball flask", you know, from a chemistry lab...." I asked if it wasn't kinda fragile, he said, "Nah, they'll bounce,.....ONCE!!" So, I got one, didn't try the bounce, just the uniformity it gave to measure-thrown charges---worked great!! Now, I know you aren't going to use that at the bench, or at a match; but that round, long-necked flask on a proper height reservoir gives a very narrow powder column that provides a greater weight on the cavity, resulting in a reduction in erratic charges caused by bridging, & a reduction in the variance in weight of less than perfect charges, which do NOT seem to occur as often, & it works w/ball or extruded powders. They are sold new from Corning Glass Works. Just thought someone might find it useful.
 
Bob,

I've found wood in powder here & there. Now you've mentioned it, the penny dropped about where powder manufacturers get their cellulose from.

John
 
Let me be a little more specific. No matter how carefully one operates the measure, different ways of doing it yield different results, both in average weight thrown, and in extreme spread of charge weights. Some ways of throwing charges work better than others. Just doing it the same every time is not enough. One has to do it the best way, the same every time. This subject is often treated as if there is nothing to discover, that it has all been published a long time ago. I disagree.
 
How about - -

Boyd Allen said:
Let me be a little more specific. No matter how carefully one operates the measure, different ways of doing it yield different results, both in average weight thrown, and in extreme spread of charge weights. Some ways of throwing charges work better than others. Just doing it the same every time is not enough. One has to do it the best way, the same every time. This subject is often treated as if there is nothing to discover, that it has all been published a long time ago. I disagree.
Click to expand...

Enlightening those of us who suck at using measures and giving us a short seminar on the proper way to utilize a measure so that we get consistent charges?

Thanks, Pete
 
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I get repeatable results by using this method. On my Harrels 90 after loading the hopper I bang on the body with a screw driver handle until there is no more settleing of the powder in the hopper. Then I throw by first tapping the hande back against the stop, just a light tap, then bring the handle forward about a 1/4 turn, back to tap the stop, then drop the load. I usually dump 3-5 loads starting just to get things working. This gives me very repeatible results. The key, which ever method you use, is to do it the same way every time.
Donald
 
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