This is a specially-adapted excerpt from the forthcoming book, “Top Grade Ammo,” by author Glen Zediker, owner of Zediker Publishing. Click here to order from Midsouth.
by Glen Zediker
Most reloaders are going to invest in a powder meter. And, right off, it is a meter, not a “measure.” Meters don’t measure. My preference would be to most accurately call a “powder measure” a “dispenser.” That’s what it really does. The “measure” is comparing a meter hopper volume to a weight on a scale. This may seem tediously technical, but I think it’s important to really understand what we’re doing when we use a powder meter. It’s a volume, not a weight. The volume corresponds to a weight, that we arrived at through adjusting the meter volume.
If you plan on relying on a meter to throw charges, and not weigh each one, you best get a good meter. If the meter is only a starting point, where you are then going to use a powder trickler to top off a scale-weighed charge, meter quality is of no real concern. A powder trickler is a device that delivers propellant a kernel at a time.
So what’s a “good” meter? Good question. The very best have Culver dispensing mechanisms. Named for Benchrest pioneer Homer Culver, these precision-made mechanisms click, just like a back sight. Each click, of course, either expands or contracts a void that the propellant fills. The only Culver-equipped meters I know of are produced by smaller shops, and they are more costly. But unlike most of the major-player meter designs, a Culver setting cannot change. There are no set-screws or rotating micrometer stems or barrels. A lot of folks give advice to “check the meter each 10 throws….” Meaning, check to see if it’s still throwing the desired weight (by the way, that would be a pretty bad meter). My experience, which has come from a whopping lot of testing, showed me that my scale was going to change before a Culver would change.
If you look at how a meter works, there’s a volume-adjustable cavity that rotates in position under the propellant supply, fills with propellant, and then rotates back, to dispense the propellant through an outlet. When it rotates, the granules contained in the meter are struck off, fixing and sealing the amount of propellant in the “hopper,” I call it.
A few things: One is that the smaller the granules, the more precise each fill can be. Longer-grained kernels have more air space and “stack” more than smaller-grained kernels. It’s also clear that the higher degree of precision on the internal sliding surfaces, the more “clean” the strike-off will be. It’s also clear that meter operation has a lot to do with the consistency of filling the hopper. Just like tapping a case bottom settles the propellant to a lower fill volume, same thing happens when filling the hopper in a meter.
A key to good throws is working the meter handle consistently, and also settling on a contact force when the meter handle comes to a stop in the “fill” direction. It should bump but not bang. I wish I could be more clear on that, but it’s a feel that must be developed. Don’t go too slowly and gingerly take the handle to its stop, and don’t slam it there either. You want a positive, audible “thunk” when the handle stops. If it’s the same each time, fill consistency will improve. I have found that focusing on operating the handle at a constant rate of speed teaches this. It’s a positive movement that, for me, takes about one second to lift the handle.
12 thoughts on “The Ins and Outs of Metering Charges”
I have only used a Harrels Premium for 14 years and I could not agree more. It is an absolutely accurate measure. Easy to set up and fast to throw a charge.
That is an old RCBS scale isn’t it? They were made by Ohaus. They have the barrel adjustment for tenth of a grain…..so much better than the little piece of tin hanging at the end of the arm like they make now. I have a new one in the box for backup. My old one that I got in a deal back in 1985 (UESD!) is STILL working perfectly!
I do have a Culver premium and it is a very good measure. However I have two Redding BR-3 AND BR-30 that do as well. Over the years I have gone to ball powders and small grain stick powders. I have found that H4895 and AA 4065 are the largest that I will not verify the load on a scale. X-Terminator LT-32 and all ball powders will throw very accurately once you perfect your technique.
I agree with the advice and premise . I just experienced a misthrow of powder into 5 cases which resulted in higher pressure and difficult extraction. The above advice will be used and my 6 powder measures tested.
I havr had really good luck with my Lee Pro and it’s accuracy. Obviously not the best with larger stick powders but for those hand loads/weighs should be done. I weigh out every 25 bullet and it is so close everytime that I seldom worry. I use cfe pistol and hp38 the majority of the time. They meter well and are almost always in stock at my local gun store.
Can you tell us what powder scale on the market gives the best accuracy? I have never heard of the one you mention. It would be nice to know which on of the “regular” powder scales that we can afford is the best. I have Lyman and RCBS. I have not tried the RCBS yes, but i also trickly each load i put in a case. I was considering going to an electronic. A better article would be which manual is best an also which electronic drop is the best. I would stick with the ones most people can afford, RCBS, Lyman, Hornady, Dillon etc…..
That is a good question, of course, because when it comes to electronic scales, better costs more. I’ve been unhappy with most of the “affordable” scales I’ve tried. Many also are re-badged. I’ve been most impressed with the PACT and the Dillon. The best is going to be Denver Instruments. Gak, though, that is pricey. The issues I have with those I’ve tried are founded around the continual re-calibration.
Other part of the question: beam scales… Honestly, I don’t know that I’ve seen a beam scale that’s “bad.” Most are going to provide accurate weight. Generally, the more sensitive a scale is the slower it is in operation. I’ve used chemistry-grade beam scales and they are indeed sensitive, but they are also a tad amount tedious. The frustrating part about using a beam scale is, if it has magnetic damping (which virtually all do) there’s a built-in 0.1-0.2 grain “tug” on the beam, depending on the strength of the magnets. Weighing lighter charges makes this more noticeable. That doesn’t make the scale inaccurate, just misleading. It’s also why I throw a good 0.2 under what I want to trickle up to.
I got VERY lucky and found an electronic scale that measures to 1/100 of a grain. I found it on EBAY in the Jewelry Tools section. Mine has been accurate as can be, ( checked against an antique but fully functional balance-beam gold scale ) and it was cheap. I tried finding more of the same to no avail. Every other one I have tried has been a P.O.S. (I was trying to find one like mine for my brother, mine is still great!) He gave up and bought a Hornady Electronic scale and now has the RCBS scale / dispenser combo. He checks one versus the other for accuracy. He spent WAY more, mine was $5 when I bought it, plus shipping. (I originally bought it to check gemstone weights) I intentionally omitted the make / model to save others the headaches my brother and I have had trying to duplicate my success.
Most digital scales have a resolution of +/- 0.1 grain. That is not the same as accuracy. The conventional scale pictured likely claims +/- 0.1 grain accuracy (most balance beam scales do.) It would be helpful to know what scale was used and what its specifications are. Note that the likely thing measured was the repeatability of the scale; a rule of thumb is to use a measurement tool 10x more accurate than the difference you are attempting to measure, thus, I would strive to use a unit with ten times the accuracy +/- 0.01 grains; in other words, a laboratory grade scale. This will truly tell something about the powder measure if operated correctly in a still air environment.
I have Redding #1 that I’ve owned since the eightys. Trust it completely. Also own an RCBS electronic that I don’t trust. I’ve got an Hornandy charge thrower that’s also old. Yes I want a Harrel charge thrower but can’t get my wallet open that wide. It’s on the wish but that’s for the future.
Your right nothing is as it was. One powder thrower doesn’t do it all to many sizes of powder. The electrictronic scales are iffy you need at least two to verify. Know wonder hobbies cost so much we’re always looking for our perfection.