Powder Scales

[New Reloader]

I have been reloading for a few months now and am a bit confused as to why I cannot seem to get accurate measures of powder from pull to pull. I have an RCBS 5-0-2 scale that came with my turret press. Before loading cases I carefully pull several loads to make sure the powder measure is accurate (so I think). During the reloading of my cases I check every 4-5 powder pulls for weight. They always seem to vary. Am I doing something wrong? Should I consider a digital scale? Are digital scales more accurate? Thanks for your replies.

[jrfoxx]

Unlikely your scale is the problem.Much more likley it is your powder thrower/measure.It may just not be a very good one, or may have a defect, or may just not work well with certain powder types (stick powders a pretty well known for not always working well in many powder throwers/measures, as they like to clog/bind up in the opening due to the shape, thus throwing the measuring off).This forum would be a GREAT place to also ask this, or any gun/reloading questions.http://www.thehighroad.org/forumdisplay.php?f=15

[K Frame]

You're not giving us enough information. Any answers that are given are going to be WILDLY speculative and may or may not address your particular situation, and in a worse case scenario could make things much much worse.

Answer these questions, and then we can make some informed comments.

1. What powder are you using?

2. What is your target charge weight?

3. The charges that vary in weight from the standard you've chosen, by HOW MUCH do they vary, and are they heavy or light?

4. What powder thrower are you using?

5. What press are you using?

6. Are you using a baffle in the powder hopper?

7. Are you taking time to settle the powder into the hopper well before you start loading?

8. Are you keeping the powder topped up to the same relative level in the hopper during reloading?

9. Have you checked the accuracy of your scale using a set of scale weights?

[brimic]

If you are using a powder thrower, it can be fairly inaccurate unless you operate it the exact same way every time. That means you need to develp a routine and follow it to the letter, any disruptions of the routine, and you need to dump the charge and dump the next charge or two until the thrower settles back in.

Some variation in weight is ok, so long as you are charging the same volume of powder.

[lee n. field]

Ditto, it's not likely to be the scale.

Get a set of check weights.  I'll bet you your scale weights consistently with known weights.  If so, it's probably your powder measure, or your technique using your powder measure.

"Came with your RCBS Turret press" -- so, probably a Uniflow powder measure?

[grislyatoms]

I have got that same press/powder measure.

What Brimic said is right on the mark, although certainly don't discount what others have said.

With that measure, keep the hopper full. I have found that if it gets below 3/4 full, the charges start to vary. Also, routine, as Brimic said, is very important.

I can kinda judge by the sound the handle makes if I am doing it properly. "Click..Clack". If I hear "Click.Clack" or "Click....Clack", I have messed up the throw. You'll get the feel for it as you do it more.

Good Luck!

[New Reloader]

Thank you for all your replies and assistance. To Mike Irwin:
1. I am using Win 231 powder
2. The target charge weight is 4.2 gr.
3. The charges vary by approximately 0.2 gr. Some are heavy and some are light.
4. The powder measure is the RCBS Uniflow Powder Measure.
5. The press is the RCBS Turret Press.
6. I am not using a baffle in the measure.
7. I believe I am giving the powderc enough time to settle.
8. I am not keeping the hopper filled as I load. I will try this though.
9. I do not have a set of check weights but they are on my "to purchase" list at the gunshow this weekend.

A buddy of mine suggested tapping the measure on the upstroke of the measure handle and on the downstroke to dislodge any powder that may be sticking due to static. It seems to be working too!

[brimic]

A buddy of mine suggested tapping the measure on the upstroke of the measure handle and on the downstroke to dislodge any powder that may be sticking due to static. It seems to be working too!

Yep, that's the ticket.

Your Uniflo should work well with ww231, it shouldn't vary any more than .1gr.    You'll have an interesting time measuring extruded powder (especially 4064) with it though, but it can be done accurately enough with practice.

[280plus]

Does anybody else start thinking catastrophe when they see the powder sticking because of static electricity? I think to myself, "What if it builds enough to discharge and spark?" Anybody ever hear of this happening?

Signed,

Scared poopless in CT 

[brimic]

6. I am not using a baffle in the measure.

Get a baffle. For the life of me I can't understand why RCBS doesn't include a baffle with the Uniflo- it just doesn't work well without one.

Does anybody else start thinking catastrophe when they see the powder sticking because of static electricity? I think to myself, "What if it builds enough to discharge and spark?" Anybody ever hear of this happening?

Its a big deal when handling black powder that's why they use conductive and nonsparking powdermeasures and drop tubes. Not so much of a problem with smokeless powder. Rub an antistatic drier sheet on the inside of the measure if you are getting static.

[280plus]

Thanks for that idea. Yea, I have a Dillon with the plastic hopper and I see flakes hanging in there now and again.

Good to know static is a bigger issue with BP too. I didn't know that. 

[Warhorse]

The two biggest problems I have experienced with powder measures is static and failure to properly break them in, causing sticking of the grains to the measure.

The first is easily solved by an anti-static spray (sometimes called anti-cling for clothes) or wiping down with a dryer sheet as brimic stated. Oh, yeah. Do not try to use the measure until the anti-static spray is COMPLETELY dry!

The second is a little harder. There is a graphite coating on most smokeless powders and simply using the measure will (eventually) coat the interior with graphite and solve both problems. It's really irritating in the interim, however. One recommendation is to use powdered mica placed in the measure and the measure shaken to distribute it. Then tap and work the mechanism until all the loose mica is out. DO NOT WIPE the mica off!
This will help break in the measure rather quickly.

Of course, after all this is done, it still comes down to using a carefully consistent procedure to throw the powder as grislyatoms already stated. A baffle and keeping the reservoir at least 3/4 full also helps maintain consistency of powder weight throw.

Even after all that, weigh the charge thrown after each set of 5-10 charges are thrown, at least until you are sure that the measure (and your action) has settled down to a reliable throw.

[K Frame]

As others have noted...

1. Settle the powder in the measure. Tapping it will work well.

2. Use a baffle.

3. Keep a consistent level of powder in the measure at all times. That will help even if you have a baffle in it.

4. Watch how you operate the press.

[Bogie]

You do NOT need check weights.

Dimes are fairly consistent. So are bullets. So are other objects. Get your selected object, make sure it weighs what it should (I use a Bart's 68 grain benchrest bullet), and you're good.
 
You need a baffle in uniflow. And, fwiw, the Uniflow just isn't going to do all that well with tiny little charges. It likes big charges. For pistol stuff, I use my Lee autodisk, and it works fine. For rifle, I use a Harrell...
 
Whacking the thing should help, but you should do it consistently. Some folks will hang a weight on 'em, pull it back to 90 degrees, and let drop. Consistency.
 
A longer drop tube can be good too...
 

 

[K Frame]

"the Uniflow just isn't going to do all that well with tiny little charges."



My Uniflow is boringly consistent with charges as low as 2.2 grains of WW 231.

It doesn't get much tinier than that.


"Dimes are fairly consistent. So are bullets."

Emphasis on "fairly."

Two scale check weights are plenty, one in the 5 grain range and one in the 100 grain range. Unless you attack them with a file they will always weigh the same.

[Bogie]

Yeah, but when you determine the weight of your dime, and put it in a little baggie, it ain't gonna change...

And Bart's 68 grain benchrest bullets weigh 68 grains, give or take a little (and the "give or take a little" comes from a scale that isn't sold by Midway... one of the first thing that one learns in benchrest is that _everything_ has tolerances - some are just smaller than others), and are perfectly adequate as test weights.
 
Do you have a "smaller" chamber setup for your uniflow? I have the micrometer dealie on mine, and just never could get into it... So I bought a Harrell...
 
Let's see...

Two Lee Auto Disk measures
Two Lee Pro measures
One RCBS Uniflow
One Harrell premium benchrest
 
And I've got two Lee scales, a couple of RCBS scales, a Dillon that Oleg, and now Tamara, has on Long-Term-Permanent-Loan, and an electronic gizmo that hates going outdoors. And I've got the ?g scale down in the basement...
 

[French G.]

The problem with the dime method is it will tell you if your scale is the same, but will it tell you if you scale is right? Might not make a difference except when following a recipe. Check weights are easy. I sealed the top of my powder measure with aluminum foil under the cap and it seems to have dissipated all the static too.

[K Frame]

"Bart's 68 grain benchrest bullets weigh 68 grains"

If you shoot benchrest grade bullets, that's great. But most people don't, and don't need to go to the expense of buying a box of benchrest/competition grade bullets. Most manufacturers have a roughly +- 3 grain variance on a 150 gr. bullet, and that much variation in a charge of a fast burning powder can be... interesting.

"Do you have a "smaller" chamber setup for your uniflow?"

Yes, but I quit using it years ago. The rifle chamber is just as accurate with small charges as the small chamber.

[AZRedhawk44]

My experience with the Uniflow is that it works better, the smaller the flakes of powder are.  Extruded rifle powders give the widest variation (IMR4895, Reloder15, etc) while fine ball pistol powders are dead-nuts on (AA#7, Win296, H110, etc).

When I reload for .308, I get +/- 0.5 gr variation with extruded powders.  That's okay for my stuff I load with surplus pulled M1 ball, but when I really want some accuracy from the rifle I shoot for about 0.8gr under my target charge and then "trickle charge" the remainder on my digital scale (RCBS Rangemaster 750).

When I use a flake powder for pistol (Titegroup, Unique), I never aim for top loads just to leave some room for error.  I typically just load blasting fodder when using those powders; stuff to harass soda cans and the like.  The only meticulous handgun loading I do is for 44 magnum, and I favor AA#7 for that which measures almost perfectly in the Uniflow.

[K Frame]

That's pretty much true of any volumemetric powder measure.

Smaller granule size means more efficient, and more repeatable, packing into the cavity.

[Bogie]

With handgun stuff, I'm generally much more concerned with avoiding double charges or squibs... I want a reliable drop.
 
Actually, for rifles, I can't tell you when the last time was that I weighed a charge... That's the beauty of the Harrell - if you write down your measurement, and then keep track during load development, all you need is the measure.

[brimic]

Most manufacturers have a roughly +- 3 grain variance on a 150 gr. bullet, and that much variation in a charge of a fast burning powder can be... interesting.

SMKs are fairly ubiquitous and are very consistant. I've never seen them outside of 0.1 gr of their stated weight and I've weighed a lot for comparison with another brand. I can tell you that Nosler J4s have a variation of at least 3x that.

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I've pretty much relegated my uniflow to the bottom and back of my remoading cabinet. On a whim, I once tried a Lee Perfect Powder Measure and found that it does a much better job of metering extruded powders. I use the Lee disc measure for pistol reloading- The RCBS is plenty accurate enough, but the disc measure is a whole lot more practical on my Lee turret press.

[K Frame]

Sierras are particularly bad, Hornadys less so.

I've never used SMKs.

[brimic]

Sierras are particularly bad, Hornadys less so

Yes, Sierra game kings do have quite a bit of variation

[New Reloader]

Thank you all for your insight and suggestions. I do appreciate them. So far tapping the powder measure handle on the upstroke and again on the downstroke has produced much more consistant charges. In the interim I have sent RCBS an email asking them why they do not include a baffle with their presses/measures.