Home Forums Reloading Big Game Rifles How accurate is your powder measure

If you are trying to get 44 grains of powder, how much over/under do you allow if you know said charge is over/under? I bought a digital scale today and it is right on with my RCBS scale. Thing is, the 4064 seems to not weigh the same each time and can go over/under a few tenths each throw. I can tell when it's going to weigh off cause I feel the crunch when I return the handle to the closed position. Was thinking about weighing each load on the digital and adding/subtracting a few grains if needed. Anyone do this?

..........Yep! After my own negative stints with a digital scale, a powder dispenser and going through the same thing I shelved them both and went back to a slower and more `ol fashioned way.

IMR 4064 apparently does not meter well on a consistent basis to give you fairly equal charge weights through your powder dispenser at a preferable + or - 1/10th of a grain...Larger kernels.

Since shelving my digital scale and dispenser and because I like my charges dead on the money for each casing, I pour my powder of choice into a heavier and lower center of gravity soup cup, scoop the powder out with the scale tray and then put it on my RCBS 1010 scale to weigh. When too heavy I dump a little powder back into the soup cup. When too light then the powder trickler takes over.

With good practice, just about each scoop of powder I take from the soup cup is roughly 2 to 4 grains on the light side. Then the powder trickler is used. Each charge weight for each casing is right on. And I do mean right on.

A slower method yes. But after checking zero, no other scale or checking mechanism is needed to check my RCBS 1010 beamed scale unit.

Just drop it light and trickle the rest in if you have to have it "right on the money". To answer your question about the powder measure, If it drops within a few tenths one way or the other it is nothing to be concerned with and will generally not have too much of an adverse effect on accuracy of a good hunting load....Now if you are talking a grain or 2 difference I'd do what I first suggested.

I just loaded 10 rounds to try tomorrow. I weighed each load with my rcbs beam scale and also the new digital scale. They matched each time so I assume all is good. Hope the rifle likes em'. I did find out that it only takes a few (3 or 4) pieces of 4064 to make a tenth of a grain. Didn't look like much but I guess it all adds up.

Here's an experiment.

Set your measure so five charges thrown and weighed together average out to the desired charge weight. Then load ten rounds with thrown charges. Load ten more with precisely weighed charges. Have someone else label and key them in such a way that you can keep the weighed and thrown ones separate without knowing which are which.

Shoot four, five shot groups, two groups from each batch. Label the groups by batch.

Now get the key and decode which groups went with which batch, weighed or thrown. The results may surprise you.

I would bet that I couldn't tell the difference between them but now you got me wondering and I will give it a try soon.

The beam scale that came in my Rockchucker kit weighs (I think) .7 grains off from a digital scale I bought for archery a long time ago. The beam scale can also show a tenth or two off in either direction with the exact same charge sitting in the pan if you just hold it down, let it go, and watch it settle itself in a couple times.

I try to be as consistent as I can, but I'm not that worried about it...

if a tenth or two is going to make a difference in my rifles, I need to find a different load with a wider sweat spot.

Sorry but I had to laugh.

Is this a wide enough sweat spot for you?

I weigh each charge to the nearest .1 grain. If the charge is a bit over I pick a few kernals out of the pan until the charge is exactly where I want it. Do I need this degree of accuracy? Probably not but it's one less thing I have to think about and there is some value in that for me.

I use a digital scale that is calibrated using the factory provided check weights.

Get yourself an RCBS powder trickler. Set your dispenser so it throws a charge 1/2 or 1 gr. less than what you want. Then, simply trickle powder into your pan on the scale until it reads precisely what you want. Pretty easy to do, and fairly fast.

I have an old RCBS powder dispenser, and it throws ball powder charges very precisely, right down to the very last charge. With a little tweaking, it can usually be set to the precise charge value, and throw most charges to that exact number, time after time. I still weigh every charge when loading my hunting ammo.

Do the experiment Mathman outlined and you'll likely never worry about thrown charges again.
I know I don't.
Throw and go for me.

I use the lee scoops and they are surprisingly consistent if you use the same technique. You do however get different results if you scoop( drag through opening first ) and tapping to level vs Dipping ( pushing the bottom in and letting the powder flow over the top). Scooping generally produces a heavier charge than dipping especially with flake or stick powders.

When I first started shooting high volume varmints I bought a 22-250 and loaded it with IMR4064. I loaded thousands of rounds with this powder before I got wise and found a powder that meters easier. Any of the extruded powders have to be trickled up to the desired weight in order to have consistent loads.

I have a Dillon electronic scale that gives me fits. It will drift constantly and I have to power cycle it to restore its mind. When I contacted Dillon (more than once) they suggested that I was at fault and not their product. I still use it, but I use it in conjunction with my balance scale. It really slows me down, but sometimes slow is better. Establish a routine and do not deviate.

Bench rest shooters have used scoops or dumped straight from the measure for decades with some pretty good results. Plus or minus .2 or .3 grains ain't gonna make a difference in the results. Especially when shooting a factory rifle with hunting loads.
If it makes you feel better cutting little logs of 4350 in two so's to get a perfect weight, then go for it but your time would be better spend dry firing or doing some live trigger time.

In very round numbers, in 30-06 size cases, .1 grain of powder equals 3 degrees F in chamber and barrel temperature. If you are not controlling your chamber temperature to within 3 F, you might as well not worry about .1 grain of powder. Results will vary substantially with powder type, of course.

The best powder dispenser I've tested (get a tight grip on something solid!) is the Lee Perfect Powder Measure. With ball powder, the random error is actually less than my Hornady balance scale. With short cut powders like Varget, the random error is very similar to that of the Hornady balance. In other words, it produces results that are as consistent as, or more consistent than my balance scale. (Old fashioned 4831 is a different story.)

If individually weighing each charge pleases you, it won't hurt anything. But it will not give you more consistent results than a cheap plastic $20 powder measure. BTW, that cheap plastic measure beat a very nice steel unit, too.

I used my Lee PPM for many many years and was never disappointed with it's function or accuracy.

Gave it away finally and have tried many other measures and none is more accurate than that old PPM.

I use a Pact scale and dispenser (the higher speed version) I calibrate each use and it is always + or - .1 of a grain. It is much faster and easier than my old beam scale. I also use a Lee perfect powder measure for my 223 and pistol cartriges and it always has worked "perfect"

Oh I couldn't disagree more!! What kind of accuracy are you looking for? I weight all charges, all brass and all bullets. Not just for bench rest ,f-class but also hunting loads. Do the test mentioned above. If your happy with results ,your done . If not load like your shooting for a national title, biggest trophy you will ever see or Trying to put 10 shots in the same hole @300 yards I use a Ohas triple beam and an RCBS digital for. All of my ,and customers loads. Scoops work but only for putting powder in a measuring devise. Then fine tuning !!!! YES IAM MR. ANNAL. But it works!!! I love guys that dump charges. It's fun to watch the shake their heads!!!

Bella1...

Some basic math that might interest you:

Random variation adds by the square root of the sum of the squares, that is total variation = square root of (variation 1 squared + variation 2 squared + ...)

So take the instance of the 223, which is much more sensitive to a .1 grain change in powder than a larger case like the 30-06.

Decent handloads have a muzzle velocity standard deviation of about 25 FPS. Let's say that is what you're getting, and that your powder measurement system is absolutely correct, all the time. Also suppose that you are considering switching to a powder measure with a standard deviation in powder charges of .1 grain, which is about right for short cut rod powder like Varget. How much with this switch affect the consistency of your muzzle velocity?

In the 223, 1 grain is about 100 FPS, more or less. So .1 grain is about 10 FPS.

The result of switching from a zero error measurement system to the powder measure would be to move from a 25 FPS standard deviation to:

square root (25^2 + 10^2) = square root (725) = 26.92 FPS.

You're going to have to shoot an awful lot of ammo to detect a change that small.

Worse, the assumption that your present measurement system is perfect is quite optimistic. Typical digital scales cannot resolve differences smaller than .1 grain. And even if they did, .1 grain of powder is roughly equivalent to 3 degrees F. If your rifle is not temperature stabilized to that, then you shouldn't worry about .1 grain of powder, either.