Powder measuring tollerance for Dillion RL 550B powder system

[Logan]

I've loaded about 500 rounds of 44-40 on a new Dillion 550B.  I've just started loading for 45-70 using H4895. Using the large powder measure I did a test to see what the variance in the powder measurement per throw was.  Discarding the first three throws, I weighted ten consecutive throws.  The measurements were 46.3 gr, 46.1, 46.2, 46.6, 47.0, 46.5, 46.1, 46.6, 46.5, 46.0.   

For ten throws the measurements differ from 46 to 47 grains.  What should be the powder measuring tolerance or accuracy that should be expected for the 550B?

Thank you.

[Litl Red]

H4895 is an extruded stick powder with individual grains that aren't very dainty.   It doesn't throw perfectly uniform charges with any measure.   But one grain variation of a decently sized charge does seem a bit large a deviation.   In a minute,  I'll go check some notes made some years back.

Some years back Accurate Arms Powder came out with 2495.  It was said to be a 4895 substitute, and one bit of advertising said it would measure better than 4895.   I think they said, "twice as accurately".   So I did some tests to see.  brb

[Litl Red]

The notes I took back then (for 308 Palma loads) show the 2495 did throw more accurately.  For charges in the 40s, the max spread 2495 gave was .3gr.   Looking at the notes brings back the memory of those tests.  TEDIUM many times over.  Digital scales weren't around then.   Glad to get more use out of that work.    The 4895 uniformity was about .5gr max deviation.   However....   that test was done using an RCBS measure, not one designed for semi-automated presses.  However....

When I got my Dillon 550 when they first came out, I wondered about how accurate it's measure was.  So it got tested, but only with pistol powders and none of those were extruded/stick.  And then Lee's Auto Disk got tested.   Also, recently I had cause to check the consistency of some pistol powders.   Biggest finding was that digital scales are excellent things to have.  As for measures............

I'm guessing your measure is pretty new.  Until the powder path is broken in (picks up "lube" off the powder) it could be contributing to variance you're seeing. 

Digital scales are worth the money, and they're dirt cheap compared to beam balance.   But what is really worth the money for a gun nut is a chronograph.   My note taking got really valuable when chronograph readings showed up.  What shows is that some powders (often the military ones like 4895) give very good velocity spreads in spite of charge weight spreads that look worrisome.   4895 and then 2495 got a lot of testing.   The holes in the targets and the numbers from the chronograph showed very uniform results.  And that was out to 1000yds lots of times, which is a decently tough test.   iirc, the M1A and 1903a3 reloads have never been trickled to insure uniformity.   

What's funny is that many of the ball powders that throw extraordinarily uniform charges will record wider MV variation than the old standby chunky powders that don't throw anywhere as uniformly.         

[Litl Red]

BTW, try some 5744 in your 45-70 if you get a chance.   You want to see uniform velocity spreads  that are often in the single digits like BP,  load some 5744.    It's velocity spread has been extremely uniform in everything from 32 to 45 (rifle and pistol) with usual bullet weights.    And it's chunkier than 4895/2495 for sure.   

[sail32]

The accuracy of a powder measure depends upon the make of the measuring device and the powder being measured.

There is a write up on one of the forums but I cannot find it.

[Logan]

With the H4895, it sounds as if I will need to weigh and use the powder trickler for every charge.

Thank you.

[Litl Red]

With the H4895, it sounds as if I will need to weigh and use the powder trickler for every charge.

Thank you.

Not at all. 

It's a powder that doesn't throw absolutely uniform charges but still gives very good performance.  Some powders do that, others don't.  It's a very popular powder with High Power shooters and has been since WWII.   I don't know anyone of us who weighed individual charges and a number who tested the accuracy of weighed versus not-weighed. 

It's easy to test. 

BTW, if you're worried so much about charge weights, you should sort your brass by weight first.   In fact, weight sorting is a great exercise for beginning reloaders.   Brass weight is an indication of internal capacity.  Some debaters believe internal capacity has more effect on velocity than varying charge weights.   Testing with your own controls will show you how important different things are to accuracy.   

[Litl Red]

Don't pass up such a great opportunity learn about your powder.

Load 10 rounds and note each one's powder charge.  Load a control group of 10 without touching the scales.  Go shoot two 5 shot targets with each 10.   

[JeffinTD]

As a side note, I did a lot of testing before I found a 45-70 load that would shoot well out of a 16" Contender pistol.

Reloaded 7 turns out to measure very well, and would put 400 grain flat nose bullets into less than 1" at 100 yards.

As a bonus my Marlin guide gun likes the same load (but not quite as accurate as the contender).

Anyway, I'd highly recommend RE7.

[Litl Red]

As another side note, the more important detail about uniformity is that a lot of powders that don't measure great actually produce uniform velocities.    5744 is the poster child for that.   It doesn't measure at all well.  It is extruded little logs that drive you crazy in a measure like RCBSs.   Yet it'll produce velocity standard deviations that are single digit.  And leave differing amounts of unburned logs in the barrel while doing it.   

Both 4895s do the same thing.  Measuring and trickling is a waste of time.  When you first get into this hobby it's normal to believe it impossible that measuring each load won't improve uniformity and therefore give better accuracy.   Get a chronograph and test it.  I started out thinking something was wrong with the chronograph.  It took more than a second test to believe it. 

There are a fair number of powders that give the same velocity spreads whether trickled to the exact same charge or just set and thrown. 

Keep in mind that unless you're sorting your brass, you're ignoring the thing that effects velocity spread the most anyway.