Home Forums Hunting & Shooting Ask The Gunwriters Question about power measure consistency

Curious what amount of variation you all consider acceptable when throwing powder charges? By acceptable I mean a variation that won't affect safety and accuracy significantly.

I have an RCBS measure and with some ball powders I get great consistency while some short stick type powders will throw plus/minus 0.5 grains, sometimes a little more. This on different magnum rifle charges of 65-80 grains.

Which short stick powders give you that much variation?

I would run the measure differently if giving that much variation out of the RCBS. My dad taught me you can double-tap at the top or the bottom, or both, and get more consistent throws out of some powders, but he always preferred to throw the charge light and trickle in the last bit to get everything equal.

I have a several throwers: a Lee plastic one, two RCBS of different sizes, and a Redding. The Redding and the RCBS do better with ball, flattened ball, or super short stick powders. The Lee does better with bigger stick powders. I alter the way I throw charges depending on how well the powder is dispensing.

I've tested a few powder measures. Oddly, one of the best I've tested is the Lee Perfect Powder Measure.

On ball powders, the Hornady balance scale has an error standard deviation of about .04 grain. So 95% of the time, you can see changes as small as .08 grain.

With 2520 ball powder, the Perfect Powder Measure is better than that. I don't know how much better, because I can't measure changes that small.

With H4831SC, the Perfect Powder Measure has an error standard deviation of .1 grain. So 95% of your powder throws will be within plus or minus .2 grains.

The Hornady Lock N Load throwing H4831SC has an error standard deviation of .14 grains.

All of these are completely adequate unless you're shooting a 1/2 MOA gun at 1000 yards. Even then, the end result is still pretty good.

Denton,

Have you ever investigated using the central limit theorem at the loading bench? By this I mean for example comparing the statistics of thrown 60 grain charges to the statistics of 60 grain charges each being the aggregate of three nominal 20 grain throws.

If it varies by more than .3 grains in a cartridge the size of the 30-06 , ill just drop low and trickle the rest in. On some of my 308 loads, i drop charges that are within a grain from one another. Sometimes ill pick a powder that gives me that type of consistency over a different powder. One reason i switched to ar comp in the 308, 6woa and .223.

My RCBS is right on with ball powder and .2/.3 with stick. I’ve learned to live with it.

I still have and use an old Herter's measure....it throws as accurately as any of the others I have.

Ball powders are always quite uniform and such powders as IMR 4320 which is a short stick powder works quite uniformly.....I always look for SSC or SC on the courser powders.....such as IMR 7828 and 4831

At the range, I've not noticed any difference in +/-.5 and none of the deer or elk I've shot have noticed.....so I set my powder measure to the norm and check weigh a dozen consecutive loads to insure that I'm hitting somewhere around the middle and load ammo.....this has not ever caused me a problem.

To your question....ball powders run about +/- .2 grains and the courser powders run about +/- .5 grains.....My favorite powder measure is the Hornady.....

If you want a powder measure that is more consistent I would suggest trying a culver type powder measure like a Harrell’s.
Even a Harrell’s has its limitations, it will throw ball and stick powder better than a conventional such as RCBS,Redding,Lee and Lyman etc. but will not throw flake powder at all !!! When using HS6 I have to dig out the RCBS.

One thing I have to admit I have never tried is mathman’s Central Limit Theorem 🤔😬

When using stick powders I don't rely on throwing charges. I throw charges about 0.5gn under and then trickle up with a powder trickler. I too have got irregular charges with the stick powders and it gets worse as the granules/logs get bigger (ADI 2209, 2213sc, 2217 and Re19 etc.). I've found if a log jams then if I apply a bit of force to cut it the charge goes up 0.2-0.3gn. If I back the handle back a bit and have another go then the powder settles a bit more and I get a higher charge. So I like to throw a lighter charge and trickle up. Then sometimes I throw a charge that is 0.7 gn under for some reason. I just done trust thrown charges with stick powders. I don't have one of those baffle thingies that is supposed to help the powder flow more consistently.

Winchester ball powders and some of the faster ADI powders (Benchmark 1 and 2) which have very small stick granules and flow just like ball powders I tend to rely on thrown charges but usually cut my charges 1/2 grain from max just to be sure. I've had my Hornady thrower for about 20 years now so the above comments are based on 20 years reloading experience. I also don't mind the extra time. I tend to treat handloading as a hobby (like tying flies) so the extra step of trickling powder doesn't worry me. I like to wait for a nice rainy day and then potter round in my loading room.

I have had several, most do quite well with large amounts of rifle powders, better will "Ball" powder. My issue is with Bullseye and small loads. my favorite load is 2.7g of Bullseye in a 38 special with a 148g HBWC. The only load my S&W Model 52 will accept. I have yet to find a powder measure/thrower that will do this consistently. Still load those by hand.

I should clarify that the absolute variation was about 0.5 grains. Plus/minus 0.25

Yesterday I noticed it with RL26 but have noticed it with IMR 7828 short cut. And also H1000 as I recall.

Has anyone tested groups sizes of thrown charges vs. individually weighed charges? And what level of variation starts to become statistically relevant.

One can not prove consistent volume with a scale and you can't prove consistent weight with a graduated cylinder

No. I put together precise ammo. I have seen such variability using stick powders in measures that I check charges with a scale. If I don't weigh it, it could be off by a few grains, due to bridging in the measure, both on the minus side, and then with the next round, on the plus side. I don't want that. And if I am going to weigh charges, I will make them exact by adding or removing powder. Why would I build crap, that could be dangerous, when what I want is precision that I can rely on, no qualms or fears included? If 60 grains shot the best in my tests, then I will load 60 grains to shoot. If 60.3 grains happened to be what I tested, and it shot the best, I'd duplicate that. I generally don't use half-grain increments in load testing with cartridges holding more than 30 grains of powder, but I will still replicate what I have tested to the best of my abilities and equipment.

Maybe it's my personality, maybe my upbringing, but I don't have tolerance for errors that are easily managed with a small amount of extra effort. And in things like guns and vehicles, I don't believe in loose tolerances. Because I rely on those mechanisms with my life.

Remington,

Plus or minus .25 grain is insignficant in hunting loads for charges of that size--unless, of course, you're trying to shoot prairie dogs beyond 500 yards. That much variation will result in about 10-15 fps in velocity with loads in the 3000 fps range.

If you are using a uni-flow, put a baffle in it. Evens out the powder weight for a more consistent drop. 6-7 bucks does wonders for it.

I've had the same exact experience with my lee perfect powder measure as you Denton.

I've also had the same experience as the OP with the RCBS powder measure.

Apparently Mule Deer tested a Lee a few years back and his experience was different but I'm leaning toward they must have made some changes recently. I think there around $20 if I remember correctly


Trystan

I did an experiment some years back comparing velocity SD for charges produced by throwing using a Lee Perfect thrower vs those produced by trickling up on a scale. I don't have my notes in front of me, but I tried a few of the propellants I use the most - Varget, H4350, 296, and a couple of others IIRC - and I found that the velocities were at least as consistent for the thrown charges, if not more so. I've thrown all my charges since.

What dan said. I used a Redding #3BR. I could not see significant differences in accuracy, velocity or SD. I will have to look for powders used but H4831SC was for sure on the list, as well as IMR4064.

YUP....this is totally believable

^^^^^^This for sure; but since going from an RCBS to a Redding 3BR long ago, I've never had cause to give it any more thought.

MM

Shot a 300 yard match this past weekend, FTR, .223 with 69 grain MatchKings over thrown (with a Lee Perfect) charges of Varget. Had less than a half minute of elevation spread out of 60 plus rounds.
A couple of months ago, shot the same match, same bullet, same weight of Varget, that was thrown light and tricked up. Went so far as to weigh loaded rounds and put them into groups of +/- half a grain. Conditions were close, not much wind, maybe a few (less than 5) degrees different in temperature. Elevation variation at 300 yards was no better, maybe even a tick worse, with the weighed charges.
So...is thrown better than weighed, or vice versa? For me, the convenience and time saved says thrown is just as good. Of course, your mileage may vary.

I used to throw all charges as well but recently went to useing an RCBS Chargemaster Lite. I doubt the Chargemaster is doing anything for me though I do like the way it works

Equal volume could be as or more important than equal weight. There are other factors involved in that.

My bottom line, shoot an audette test, it will tell you how much powder variation matters at your chosen node.

And a chrono can't tell you how your rounds will group either, FWIW, it can guess well, but what matters is what holes in paper tell you. Thats all thats ever really mattered.

I've done similar testing over many different days and several loads, rifles, and chamberings. My results are similar to yours.

Belding & Mull Visible Powder Measure

After reading some of the results you guys are getting......I don’t feel too badly about my 60+ year old Ideal #55. It does fair with most powders (real good with ball powders), if I follow my powder dispensing regiment religiously! memtb

Just about every stick powder I use gives me enough variation that I am not comfortable with charging direct to the case.

That discomfort can be overcome Jorge. With 4895 in the 308 I've shot many sub-moa 15 shot groups with thrown charges.

Unless I'm loading only a few cases, all my powder charges (including stick powders) have been measure-thrown for many years.

Part of the worry many handloaders have over thrown charges is due to a conviction that a slight difference in the Magic Powder Charge for their rifle will result in "fliers." But other factors are far more important than, say, half a grain of powder, especially in magnum-sized big game cartridges holding more than .30-06-sized cases.

Most hunters would be far better off worrying about case-neck thickness variations, seated bullet alignment, or velocity variations due to heat/cold than miniscule variations in powder charge. But that's not the way many think, probably because their handloading mentors emphasized "precise" powder charges. One of the older handloaders I knew in my 20's would even cut a granule of IMR4350 in two, to balance the scale "perfectly."

The other factor, of course, is that so many handloaders accept the notion of precisely weighed powder charges being extremely important to accuracy that they've never actually tested whether it's true.

It sure would save me a lot of time. Matter of fact, was loading some 308 with 46.5gr Varget and could not get consistency of +/- .5 . if you are saying that's ok, I'll give it a shot

Especially when the handloader is not shooting long range benchrest with equipment that can resolve the difference.

What measure are you using? Does it have a baffle in the powder column?

That's more variation than I get with Varget.

Volume loading powder verses weighed loading powder thats been a argument for handloaders for years. ammo factories always volume load. most 100-200 yard bench shooters volume load and they shoot some very nice 1 hole groups. FTR shooters do both but my friend who shoots alot of 600 yard competition and is 71 years old and always does well volume loading. i was taught by a ballistic engineer at a ammo factory: powder can not be weighed accurate and volume loading is more accurate. my testing with a a Remington 40 x target rifle volume was more accurate at 100 yards also. to this day i wonder why someone has not really gave me or anyone else a better answer, so i just volume load, i still wonder what is the best way > volume or weighed powder ? maybe Mule Deer has the better answer to powder consistency? i use all Redding benchrest equipment i am very consistent with my Lapua Brass.

I'm a bit surprised that no one else mentioned the flat consistency of that old design. Since switching to a Harrell's from my old tried and true B&M I honestly don't know why I did. I keep the B&M handy though for measuring .45 pistol charges of Bullseye and that's about it. I insist on using the Harrell's not because it's better for my rifle reloading but because it's shiny and pretty, and cost a lot.

I too used to worship at the altar of micro-precise weighing of each charge, and then saw the light and quit wasting my time.

Switching to premo loading dies and paying attention to case neck variables paid more dividends when shooting my "ego massaging" rifles. Once again, Mule Deer is right, the rat.

Hornady and yes I have the baffle installed, but it happens with just about all stick powders especially the slower ones.

I haven't worked with a Hornady measure, but I do recall reading some comments here about not getting the most consistent charges with them.

I mostly use a Redding BR-30. I use a slow, high torque throwing motion. If grains act like they want to get cut then they get cut, they do not hang up the measure. I don't do any of that tapping at either end of the stroke.

When I load a long stick powder like 4064 or 3031 I don't even weigh individual charges. I throw 10 together, weigh the aggregate, slide the decimal point over one place and that average weight is what I name the charge. The targets tell me whether or not variation is acceptable.

Varying charge weights will mess with the Extreme Spread (other factors will do this as well). An Optimum Charge Weight load is more forgiving for small variances in case volume, neck tension, and inconsistent COL etc.

This requires the correct powder for the components used.

A 308 Win as well as others (considered an inherently accurate cartridge) exhibits this.

OCW load will give the best chance of small groups. However, if the load is not on a vibration node groups will not be as small as they could be, excluding other mechanical factors. So you need an OCW/Optimum Barrel Time load.

Back to the measure, I use a Lee dipper dumped into a pan on the FX 120i digital scale and trickle up, variance is 0.00gn/0.02gn.

This is a slow way to do it, but gives very good results for range work and competition. I also use this method for hunting rounds.

At the minimum many 1/2 moa groups (at least 5 shots) at 100 yards will more or less prove that your rifle/scope mechanics are good. At distance your scope must hold zero and track reliably.

To prove a good load for hunting or competition push the distance out to 300+ yards, once you get good 5 shot groups move to 10 shot groups. This will show you a load that will stand up at distance.

The Extreme line of powders are quite good but it is the air temperature that messes with POA/POI from day to day.

I respectfully submit no matter how good the ammunition, scope and shooter, the heavy majority of big game rifles for which handloads are being assembled are not capable of repeatedly/reliably producing 1/2 moa five shot groups.

The shooter and the environment are tough to control variables.

I look at OCW,OBT and ES, and rifle/scope mechanics . If these markers are good then the problem lies with the shooter and his/her interpretation of the environment .

Chasing ones tail is counter productive.

I run the same scale coupled with an auto trickler. Depends on what your time is worth, I can dump enough loads to cover a 60 round midrange match in less than an hour and hold the tolerance you speak of.

.1/2 grains of varget equals 25 kernels of powder. I'm curious on what chronograp and what parameters people are setting when they say a dropped load is as consistent as a weighted load. 25fps variance on a .308 at 600 yards drops you out of the "10" ring...

I use a Labradar, FX120i scale, ability to use good measuring tools and Quickload to figure out a good load.

Need single digit ES to compete, this carries over to my hunting handloads.

A recent example is a new to me Steyr 7mm-08, 6x MQ SWFA, 150gn ELD-X, 1038 yards 6.25" 3 shot group. This is my back up big game rifle.

jorge,

Have you experimented with the height of the powder baffle inside the measure's tube? That can make a noticeable difference in consistency.

M.D. >i do use the long neck type piece under my Redding Benchrest powder measure and my baffle is between 2-3 inch above the powder cup cylinder is that about right height ? my question still is can gun powder be weighed accurate ? or is volume loading more accurate ? at the 100-200 yard bench matches they all volume load some use a 1-10 grain adjustment some use a 1-18 grain adjustment powder measures,most shoot 2`s and 3`s at 100 yds sometimes better too with their 5 shot groups.

Pete,

The best way to determine baffle height is to experiment--with the powder you want to use. The best height will vary not only with the measure but the powder.

In general, it works to use a smaller powder measure for smaller charges, and a larger one for larger charges. I have several for various purposes, including one of the Lyman 55's with the Homer Culver micrometer conversion that Ken Oehler very generously gave me a few years ago. For many years that was the preferred measure by short-range benchrest shooters, and it still works VERY well.

The other side of powder measuring is that charge weight doesn't always mean consistency, since powder weight for a certain volume can vary with humidity and storage. Each time you open a jug of powder it can either gain or lose weight, due to humidity. It can either gain or lose weight, sometimes meaningfully. Weighing the same amount of powder many NOT result in the same results, while volume may come much closer.

Which is why proper powder storage--and leaving a container open as little as possible--can make a difference in velocity and consistency. However, whether this matters or not to most handloaders is another question!

thank you Mule Deer ,i do have small and large Redding powder measures, i also have a reloading room that has a wood floor with plastic underneath my marine plywood ,i have electric base board heat for controlled dry temperature. i did screw up with size of this room its only 8x16 -8 feet high ,if i did it over 12 x 24 -8 feet high but i would still have the wood floor with electric heat. and again thank you,Pete53

If a .5 variance is insignificant, answer me this. Folks often post ladder test results here and see appreciable differences within a .5g range. What gives?

I'd be more impressed by ladder tests if more than one or two shots were on each step of the latter.

The appreciable differences your seeing are most often caused from other factors, wrong powder, wrong primer, runout, etc, etc........ This is a short answer to a complicated question but in a nutshell if your seeing appreciable differences with a small change in powder charge there is a problem somewhere and it isn't the powder charge IME

It is possible to see an appreciable difference if you went from the edge of a node to out of the node however once you have achieved a load that is in the middle of a node .5 grain of powder isn't enouph to put you out of the node. I'm basing my reply off of the assumption that were talking about .5 grain of powder effecting a proper load at reasonable distances.

With a good load Ive not seen much that can be noticed even at 500 yds which is further than most hunters ever shoot

A long time ago in a far away land, Kenny Jarrett told me not to think twice about +/- 0.5 in a .280AI.

Battue, I have noted that cartridges that are loaded to "higher powder operating pressures" are effected less concerning velocity when powder is added or taken away. Your mileage may vary but IME both the 280 AI and the 270 that have a high Sammi pressure rating benifit from this from what I have seen.

It doesn't surprise me that Kenny specifically mentioned the 280 AI due to its 65,000 Sammi pressure especially if he was comparing notes to a standard 280 that is much lower

It is for this reason that I have come to appreciate loads where accuracy is achieved at pressure! I'm also quite sure its one reason why bench rest shooters often run what we might consider almost insane pressures

Why charge consistency matters less than most people think it does....

The muzzle velocity of commercial ammunition that I have tested has a standard deviation around 35 FPS. Assume for a moment that you have some kind of powder measuring device that is slow and laborious, but gives absolutely perfect weights every time. With this wonderful device, the standard deviation of your handloads is a very acceptable 30 FPS.

Now, for the sake of illustration, suppose a travelling salesman drops in on you and offers you a much faster but sloppy means of measuring powder, and the performance tradeoff is that the standard deviation of your powder charges will jump from zero to .15 grains. What will this do to the standard deviation of your muzzle velocity?

If you're loading your trusty 308 Winchester with between 44 and 47 grains of Varget behind a 150 grain bullet, you're loading in a region where an additional 1 grain of powder yields an additional 50 FPS. So .15 grains of powder is 7.5 FPS.

Now we can combine the variation due to all other factors, SD=30, with the variation of the new powder charging device, SD=7.5 FPS. They do not add linearly. The formula is

Square root (30^2 + 7.5^2),

and that is square root (900 + 56.25), or 30.92 FPS.

The decrease in the precision of the fast but sloppy charging system changes the standard deviation of the muzzle velocity from 30 FPS to 30.92 FPS. That is not enough to worry about, and most powder measures are better than SD=.15 grains.

This is a pretty good representation of what happens with mid to large size cases.

John,

Have you ever experimented with "Double Baffling" in a powder measure? I.e. Using two powder baffles in tandem, with one on top of the other rotated 90* (with the upper baffle placed with its drop slots perpendicular to the those of the lower baffle). I've read that it will further increase the consistency of a powder measure over using a single baffle. This tip was shared by a knowledgeable handloader who's opinion I trust, but I've never bothered to add a second baffle. I was curious if you had and what you may have found?

Thanks.

No i have not. I just have the standard baffle that came with the kit, but I'm open to learn!

Never going to knock the search for consistency since that's the name of the game in accuracy, but in the real world of sporting rifles how much effort vs. reward are we talking here?





Fwiw, the 6 powder baffles in my measure are moly coated and drop individual kernels through a laser reader which counts each one*. My razor also has 12 blades for a really close shave...













* Mathman, before you ask, the answer is yes. Kernels are also checked for size consistency and moisture content and those outside of user specified parameters are routed to a dump chute for use in plinking and short range off hand practice loads.....

I'm not one of the powder charge OCD types around here. I run 3031 and 4064 through a measure.

Thanks, Denton, math will show you that weighing every charge is a waste of time.

I record the setting on my measure and once I've worked a load up, load by volume only. I have tried it enough times to convince myself that if I change powder lots, the velocity is more repeatable by volume than by weight.

I throw a little low, then trickle up to the correct weight. I have a couple Redding powder measures. Varget throws really well, so does CFE 223. I load middle of the road pistol loads, so I throw them right in the case, weigh every tenth one.