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

I currently have three powder measures, one RCBS Uniflow and two Lee Perfects. I did a little informal experiment last night to see how accurate they were, and I used two very different powders. The first is a bulk ball powder, similar to H335, which has always metered very well. The second was IMR4350, which is an extruded powder. I dropped eight loads per powder on each measure, and here were the results:

RCBS: Ball Powder
Mean: 33.46gr
Standard Deviation (SD): .13024
Extreme High: 33.6
Extreme Low: 33.3

Lee #1: Ball Powder
M: 27.4
SD: .13228
EH: 27.5
EL: 27.1

Lee #2: Ball Powder
M: 35.875
SD: .10350
EH: 36.0
EL: 35.7

Using IMR4350
RCBS
M: 32.025
SD: .6475 (exlude the EH, and the SD drops to .35923)
EH: 33.4
EL: 31.5

Lee #1
M: 25.42
SD: .2201
EH: 25.7
EL: 25.0

Lee #2
M: 33.037
SD: .33754
EH: 33.5
EL: 32.6

As you can see from the numbers, the SD changed significantly in going from ball to extruded powder. I realize extruded does not meter as well as ball, but I didn't expect the SD's to change this much. One note on the RCBS Uniflow measure, you could feel the extruded powders "catching" or "breaking" during the dumping process, which I am sure affects the results. The Lee measures remaind smooth throughout, but still weren't "perfect".

Of course, what does all this mean? Realistically, very little. The sample size is relatively small, and should incorporate at least 25-50 drops. However, I think a little can be taken away from this. I would have no problem loading a batch of ammo with either measure using ball powder, but I would be a little hesitant in using them for stick powder. I do load a lot of pistol and rifle ammo using ball powder, so these measures should work great for me.

Anyone else checked their measure, and how accurate was it?

I found your info interesting. I have an rcbs but have heard the lee is more accurate with stick powder. I have always noticed that if you feel a "catch" when cranking the rcbs that it always results in an overcharge...or at least one of more wt.
I think I have read that there is something adjustable like a wiper or something on the lee.....is that possible?

Honestly, I am not sure. I have never tried adjusting the Lee, and was unaware of any tweaking you could do. I can say this, I experienced a "catch" with the RCBS on almost every drop with stick powder, but only felt one with the Lee measures. I do believe a little more experimenting is in order before anything is conclusive, though.

i have a old belding & mull that was made in the 50's that is the most accurate i've ever used.

I`ve a "Quick Measure" that seems to do as well with stick as with Ball powders. I`ve never realy tried to campare them as you did however.
I use extruded powder almost exclusivly except for handgun ammo and my measure sees very little ball powder for larger rifle charges.

The question is, at what point does the accuracy start affecting accuracy? I would think +/- .2-3gr wouldn't make much of a difference, but I have no way to quantify this. Anyone have a guess?

That's where the ladder test and the OCW load development method come into play.

I went out to the shop and ran a few strings through my Redding BR-30 measure. I used four powders suitable for the 308 Winchester since I load a bunch of those and I prefer to throw charges for production runs.

For each powder I started by filling the hopper about half full and throwing ten charges to stabilize the powder stack. Then I weighed and recorded a ten throw string. No charges were censored because of crunchy throws or any other reason. I used an old PACT digital scale that was turned on for about ten minutes before the test. I checked its calibration at 20, 40, 50, 70 and 100 grain levels and it was spot on.

[powder, sample mean, sample std. dev., extreme spread]

[Varget, 44.11, 0.137, 0.4]

[H4895, 44.03, 0.09, 0.3]

[RL15, 43.12, 0.117, 0.4]

[IMR4064, 41.59, 0.145, 0.5]

Frankly I was suprised at the good performance with the "Lincoln Log" IMR4064 given the crunchy feel of the throws.

I like the OCW idea and loading with a broad accuracy node in mind. If a load is so sensitive that +/- a tenth throws it off accuracy or pressure wise then what's a seventy degree temperature swing going to do to it even with precisely weighed charges? Of course I'm not shooting at a thousand yards where small MV differences may make large vertical differences.

I own 2 Lyman 55, 2 Bonanza, an RCBS Uniflow and a Harrel's. The RCBS remains mounted on my Hornady Pro-7 press (pistol loads) but I haven't used the others since I bought the Harrel's. It's much more accurate and so easy to dial up to a given load (I made up a chart with all loads/powders I use).

I use a Lyman #55, never tested it, but I very rarely trickle or remove powder from the pan, and I weigh every charge. Ball powders it is invariably virtually perfect.

An obscure and underpaid writer did an article about this in Varmint Hunter a while back, testing the Lyman 1200 digital scale, the Hornady balance scale, a Lee Perfect Powder Measure, and a Hornady measure.

Using ball powder, of the four the Lee was the most repeatable. It beat out all three of the others.

Using Varget, the Lee and the Hornady balance scale tied for first place.

All that said, all four alternatives were completely capable of producing charges as consistent as practically anyone could want.

Because of the non-linear way that standard deviations add, it is a waste of time to individually weigh charges. Also, sometimes the powder measure is more consistent than a good scale.

I have a Lyman #55 That has been in use since 1971. It is one of the old ones that is brass inside for use with black powder. No matter the powder I have tried it runs no more than + - .2 Grain. Perhaps that is because of familiarity but it always works. Fill the hopper, run 10 charges to settle and start with the handle down raise it to fill the reservour and a smooth down stroke to fill or measure. Been doing it that way for 38 years and my Wife also uses it with the same result, (she is GOOD with a powder measure and electronic scale). Bear

This got me curious, so I went out and tested my Harrell measure. Each container of powder was at least half full. When putting on a new container, I threw 2 charges before weighing, and I used the same "technique" with each throw. Weights were measured with a RCBS 505. I also did not change the dial setting on the measure when switching powders. I did get some "crunching" with the "long stick" powders.
I threw 5 charges with each powder.
I didn't figure SD or such, but here are the results:

"long stick"
IMR 4831 - High 34.0; low 33.9; spread 0.1
IMR 3031 - High 31.8; low 31.6; spread 0.2

"short/medium stick"
H4895 - High 34.1; Low 33.9; spread 0.2
RE 15 - High 34.0; low 33.9; spread 0.1

"ball"
AA No5 - High 39.0; low 38.8; spread 0.2
H335 - High 39.7; low 39.6; spread 0.1

Which is the best powder throw set up available today?

Is the lyman 55 still made as well as it was before?

I don`t know what is the "Best" today, but if I was in the market for a fast, accurate way of charging brass I`d concider a digital scale/measure like the Lyman 1200, or RCBS Chargmaster. Nothing I`ve seen in a measure will keep charges of all types of powder to a +/- 0.1gr tolerance . These should be as accurate as the scale.

I can get a Lee with in 5 sticks of 44.7grs of IMR4064 half the time,the other half of the time,it's on. But I'm only using a 5-0-5 scale.But that all depends on my wrist action. The measure has been grahited and the screw adjusted. It's my match load.

How do you graphite the measure?

richard

My Harrell's Premium Powder Measure is a cool tool. I have been testing it extensively and get less than 2% variation on most all of my powders from long stick to fine powder. I weighed every charge with my Lyman DPS 3.

It's a keeper.

Run 1/2 a can of powder through it and the powder will leave enough graphite to coat it. Plus it`s good practice to get your throwing technique down pat.

I am still using mine, and it is very accurate. Mine was produced in the 70s, and I got the vernier tubes...jim