Home Forums Reloading Big Game Rifles Measuring powder charges

Whether it does or not, if you simply want to it, that's reason enough.

I also use the Acculab VIC 123 scale. I can truly see single digit SD's and low, less than 30 ES's when I get my powder to +/- .02 gr.

Alan

Never let it be said that I told anyone how they should/could twittle away their time. I do have a problem with the folks that try to portray that wasting the time elevates them to some sort of high road of reloading and we ordinary folks that would prefer using our time more wisely (like actually shooting) are the lesser mortals.

I seldom use very fine rifle powder, such as ball powders.

My mainstays are H4831SC, IMR 4350 and H4350, and a few others of similar coarseness.

I do use a measure to speed things up, set it (an old RCBS) just under the desired charge and trickle with my fingertip and thumb to desired weight. Because most of my loads for hunting are near maximum, I want to ensure that the deviation doesn't go on the high side.

Loading handgun ammunition, with fine powder (mostly 2400), I use the measure exclusively (checking the charge it's throwing often).

You're the first person I've read who does the same as me. I can obtain the accuracy I want with thumb, forefinger (put) and tweezers (take).

Alan

I'm too low tech to even use tweezers - I use a small aluminum bunt/cake pan, use the center "tower" as my bumping post and just dribble out granules from the scale's pan.

Holy [bleep]

WOW, I thought I was anal retentive about my reloading process, but after seeing what some of these folks do, it makes mine look like I got the runs. WOW

Swifty

I have proven to myself many many times on dozens of cartridges, that even with stick powder, trickling and weighing every charge is a monumental waste of time. Also, it might do some of the chronic weighers to consider how a beam type scale works. If the knife edge of your beam gets a small degree of roundness to it, your accuracy is gone. The more you use it, the more this will happen, particularly if you leave the beam on it when you aren't using it, and it moves every time the heat/ac fan comes on. I have kept good notes and use a measure with a micrometer adjustment, and set the measure by my notes, and don't even weight any of them, once a load is established. If you spend years loading lots of different calibers with lots of different lots of powder, you will find that the velocity of you loads will vary less when changing lots of powder if you set by volume rather than weight.

In other words, change lots, set your measure to the precise volume that you worked up your load with, and don't even weight it. Shoot them over a chronograph.

Load some with the new lot, and set the weight by your scale. Shoot them over the chronograph.

Compare the results to your original load, every time, and the results will tell you that there is more variation of pressure by weight than there is to volume when changing lots.

i use a antique belding &mull powder measure set a little light then trickle to perfect.i collect the old measures so i have plenty to choose from.

I haven't used a powder trickle since Clinton was in office.

Agree w/ your point insofar as accuracy is concerned, but don't think this accounts for a maximum load of stick powder. The measure setting in this instance must accomodate the extreme spread, such that the charge must be slightly less than the max charge. The argument that this small velocity loss is insignificant in the big picture is a good one, but as others here have said, I'll take that little bit extra.

I don't really know why, but I never work up loads without trickling up to desired weight on a scale. Since the late sixties I have used a Chronograph with workups too. If I am going to load a bunch (more than 20) I set the measure and drop into the cases, I never trickle. If I am just loading a box or so I trickle each one. Habits die hard.

I do the same. I trickle up on big game loads which I'm never doing large quantities of. For varmint/target stuff I use good metering powders and dump directly into cases.

When you are developing a load, when you find the sweet spot that gives you the best accuracy, work, in small amounts to either side of that sweet spot until you see just how much variance there is. Then center your load in the middle of the sweet spot. This should take care of any +/- you would have with thrown or dipped charges. (assuming you have a well practiced stroke with your powder measure or dipper)

If you want to get single digit SDs, you have several sources of variation to deal with: case capacity, bullet weight, powder weight, neck tension, etc.

If you are using a balance scale, you are measuring mass. Most digital digital powder scales measure weight. And because the g constant varies over Earth's surface, the weight of an object is about .5% more at the poles than it is at the equator. Mass is constant, regardless of where you are. So a 50 grain charge measured digitally at the the poles would weigh 49.75 grains at the equator. That's a 1/4 grain factor that nobody seems to notice or worry about. Plus there is another 1/4% factor if you happen to be at the top of Everest... but I understand the hunting there is not so good.

But if your quest is consistency, you don't care about systematic errors like that.

So, if you have a .5 MOA rifle (243, 75 grain bullet, 3,400 FPS, 1 grain = 75 FPS, a favorable set of assumptions) that never shoots fliers, and you're shooting on a perfect windless day, and if the rifle and cartridge are the sole source of random variation, and if your cases all have exactly the same capacity, and your bullets all have exactly the same mass, we can calculate the shape of your groups and see what influence better SD has:

At 500 yards, with a 15 FPS standard deviation, your groups would be ovals 3.2" tall and 2.5" wide.

Switching to a really terrible powder measure with a .25 grain standard deviation (extreme worst case assumption), your MV SD would increase to 24 FPS. Now your 500 yard groups are 4" tall and 2.5" wide. (I have tested the Perfect Powder Measure with Varget, and it gives a standard deviation of .11 grains. Under this condition, MV SD increases from 15 FPS to 17.1 FPS rather than 24 FPS.)

Without doing the math, I expect that you'd have to shoot hundreds of rounds to even statistically detect such a change.

And in real life, the change is much much less than that because all the cases don't have equal capacity, and all the bullets don't have the same weight or mass, and the major source of random variation is probably the shooter. As stated, in very round numbers 3 degrees F change in barrel temperature is about the same as .1 grain of powder. If you're not controlling your barrel temp to within 3 F, there is no point in worrying about .1 grain.

Great post, Denton.

I throw powder charges directly into the case for cartridges from .223 to 7RM and 7WSM. In favourable conditions, I can often shoot sub-3/4MOA groups out to 1000 yards with these loads, with the odd group going under 0.5MOA at various ranges.

A 10-shot string over the chrono has produced SD's right around 10+/-, and an ES of under 15-20, on various occasions.

That's good enough for me for target shooting and hunting.

Thank you denton, for such a lucid and succinct explanation. There is no substitute for knowing your subject!

I will stay with confidence with my more than 40 year old Lyman 505 (Ohaus) scale (carefully removing the balance beam after each use), my equally old Lee dippers and my flimsy feeling but surprisingly consistent Lee powder measure. Fully aware that the overwhelming source of error in my shooting is me. Not my equipment.

Denton is correct that Beam scales measure mass, but he is incorrect in assuming it is not affected by gravity. A beam scale uses torque to measure GRAVITATIONAL mass, a otherwise, how would the scale move if gravity wasn't paying a role? The same inconsistencies that apply to a digital scale (or spring scale) apply to a balance scale as well, although a spring scale is more likely to be affected by a change in gravity.

The important thing is that you are constant with your measurements and how you measure. So long as you weigh your powder in the same place, and all to the same weight, there will be little to no inconsistencies, all the powder should be the same weight because they were measured under the same conditions.

I will agree, though, that the rifle is also a source for inconsistency, but it is such a small source that most shooters can't shoot good enough, and most chronograph aren't accurate enough to measure it. If anything, the chronograph is the biggest source for inconsistency when trying to get a single digit ES, and imo, that is also unchangeable.

Speaking of H4831sc......I have some and use it with 150 BST's. I've noticed this powder looks just like the Retumbo I have. Where does the "sc" play into it?