Powder Measurement and Extreme Spread of Velocity Question

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Powder Measurement and Extreme Spread of Velocity Question

Postby Mr. Glock » Mon Jan 09, 2017 10:02 pm

As many regular forum handloaders know, I bought a Lee Classic Turret press set up last year, to play around with reloading. I pulled it back out this winter. I've decided a good way to use my set up is to load up 38 SPL and 44 SPL, since they are quite pricey in the retail stores. I just want plinking ammo, and I don't need to crank out tons. The whole process is working out well (i.e. consistently ) except for the powder handling.

I had some issues with the powder being sticky last year due to static cling, and someone recommended using graphite on the press parts etc, which has worked well on this go-round. I'm using Unique. I have a well-proven chrono, and I've been out in the recent 25-45 degree weather.

I tried a few different ways to load powder:
1. Lee Dipper: This really didn't work very well at all with the 44 SPL/ 240 gr, with velocities all over the place by a couple of hundred feet and two squibb loads getting stuck in the barrel. Really hard to get a consistent fill level.
2. Lee Pro Auto Disc: I like the concept here, which is ease of use and powder cleanliness. I chron'd 12 rounds in 38 SPL/158 gr, and my extreme spread was 108 fps, ranging from 751 fps to 643 fps for 5.0 grains. When I test weighed, the weights ran from 4.6 to 5.1, but mostly closer to 4.8 to 5.0.
3. RCBS 505: I loaded up five 38 SPL/158 gr rounds being very careful to measure each one to 5.0 gr with a powder trickler, this gave me an extreme spread of 52 fps, ranging from 790 fps to 738 fps. But it takes quite a bit of time, and I spill powder around too.
4. MTM Digital Scale: I also loaded up these five rounds very carefully, but this had an extreme spread of 137 fps, from 804 fps to 667 fps.

What should be my expectations for overall extreme spread of velocity with each method?
Am I missing a good, efficient method of powder handling?

PS As for safety, I'm shooting both SPL loads in Ruger MAG wheel guns, so I have a large safety margin in case I make an error.
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Re: Powder Measurement and Extreme Spread of Velocity Questi

Postby sparky43040 » Tue Jan 10, 2017 5:25 am

Personally I never thought one could expect very accurate loads from a turrent press.

I loaded thousands & thousands of rounds with a single stage RCBS Rockchucker and used a RCBS digital scale & RCBS powder distribution center "thing".

I never had a way, other than punching holes in targets, to check/test accuracy, but my loads were all better than store bought.

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Re: Powder Measurement and Extreme Spread of Velocity Questi

Postby mreising » Tue Jan 10, 2017 4:41 pm

My experience with the lower end digital scales is that they are not very consistent, especially with small amounts. I had reasonably good results with various powder measures, especially the Lee, after "graphiting" them to bleed static but most important is consistency in how you activate the measure; variations in speed or force will change how the measure throws a charge. For my loads that were going to be at or near maximum, as well as those for competition, I always weighed each charge.
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Re: Powder Measurement and Extreme Spread of Velocity Questi

Postby Sevens » Mon Jan 16, 2017 8:14 pm

There are actually many items I see in the description of the problems that have possible answers or solutions. I'll do my best to help.

First... you say that you have a chrono that you trust but I believe there are a LOT of things that can cause poor chrono results beyond simple powder handling problems that you may have. In a recent thread Morne had, I talked at length about the other things that may affect chrono results-- a big one is crimp/neck tension and this could be due to wide variations in your brass or the QC in your bullets or possibly in your technique at the bench. It could also be due to your habits of the physical act related to how you hold the handgun while sending shots over your chrono.

You seem to think that your powder handling is the culprit -- this may well be the case. Me, personally? I loathe Unique. Unique is a "hall of fame" powder and I could never take away the stamp on history that Unique owns but that stuff is only still made today because crotchety old men love it and still buy it. The only guys under 30 that buy Unique were either taught by a crotchety old man or were GIVEN a stash of Unique.

Unique can effectively be used in a zillion places, it earned it's legendary reputation that way but it meters like crap, always has and always will until they put it out of it's misery. "Poor metering" is a handloader's term that basically means that typical volumetric powder dispensing tools just don't work well with it. Unique has big, dumb chunky flakes and it meters about as badly as any powder on the market.

On top of that, you are using a real budget powder measure in the Lee Auto Disk or Pro. I don't intend to make a color or "brand war" and I use a serious bunch of Lee equipment myself, but the AutoDisk is not a tool that I am interested in using. Some folks get fine use from them (I know that SuperMod Evan Price definitely has had fine service from them), but my true love in a powder measure is the Lyman 55 which is, IMO, far better than the Lee AutoDisk. But even with my Lyman 55 I would never expect success when dealing with Hercules "flaming dirt", better known these days as Alliant Unique.

The MTM electronic powder scale is also a liability, IMO, and it is either reporting nonsense right now or soon will be. A good beam scale like your 5-0-5 is all you may ever need for weighing charges and setting up a quality powder measure with a decent metering powder.

Given what you have reported, I think the quickest and easiest and cheapest route for a quick chance at genuine success (or radical improvement) is to go out and buy a modern powder. AA#2 or the fastest one from Ramshot (Zip, maybe?) or Win231/HP-38 or Titegroup or any of a half dozen others is a $20-$25 method to likely see instantly better results.

I'd suggest that first, then test and report back.
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Re: Powder Measurement and Extreme Spread of Velocity Questi

Postby Mr. Glock » Sun Jan 22, 2017 1:26 pm

So I picked up some Win 231 and some Accurate #5, to use in both 38 SPL and 44 SPL. Both metered much better in the Lee Pro Auto Disc, especially the Accurate #5. I started with 38 SPL.

After checking the initial set up, I measured each fifth round and loaded 50 rounds of 38 SPL of each powder. The Win 231 grew .3 grains over time, but the Accurate stayed exactly the same grain weight.

After checking speeds, I fired and chronod 5 rounds twice in a snubby for each powder. Extreme spreads were 47 and 47 for Win 231 and 27 and 72 for the Accurate, with a very similar average speed both times. This is much improved, and overall velocity was around where it was supposed to be.

Interestingly, in a 6" gun, both powders had much larger extreme spreads. I fired 6 rounds twice of each powder too The Win 231 was 153 and 293 (there was one low outlier in that batch, dropping it out gave almost the same extreme spread). And the Accurate was 185 and 195.

I used the same methodology for each gun, which was picking a set number of rounds from the beginning of the run, the middle and the end. And I rotated the 6", then snubby through both powders (i.e. both on one powder, then the next powder, then repeat). I also checked the chrono with some factory Cor-Bon in the snubby, which was very tight as expected.

I solved my major issue, which was very high deviations in velocity due to inconsistent grain weight, so feeding the Unique was definitely the root issue causing problems. And both these new powders are not nearly as dirty nor spit out burnt powder.

But, I'm wondering how the extreme spread could be so different in two different guns? I did notice that the Car-Bon fired in the 6" also opened up the extreme spread. Would different (i.e. variability in) chamber throats lead to an extreme spread difference too (that's about the only thing I can think of)?

I have some old chrono data for the 6" with factory loads vs other guns with the same loads. And there are ways to test chamber throats, but I just haven't done it yet. Figured I'd toss it out there now, though.
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Re: Powder Measurement and Extreme Spread of Velocity Questi

Postby Sevens » Sun Jan 22, 2017 1:47 pm

You might need pin gauges to check chamber throats but the poor man's method would be to number the chambers and then simply use just one chamber each time.

I might also suggest that .38 Special is always going to be a little funky to work with in that it's a large volume but low pressure round. In most instances of handloading, the rounds that work the best have used up most of the space and are also typically near max pressure for the round.

Lastly...
I am a firm believer in the idea that chronos create as much drama as they solve, really. Getting an idea of bullet speed for a number of good reasons is one thing, but there is a time to cut the cord and put the loads on paper and let the paper tell you loud and clear which loads are the best and leave the little fun-sucking box in the closet. ;) But I admit that the chrono has often annoyed me. And I made 20+ years of phenomenal handloads before my first shot ever over a fun-sucker.

IMO, it's best used to gauge speed for the purpose of estimating bullet drop over long distances. Beyond that, it'll just drive you a little nuts -IF- you let it.
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Re: Powder Measurement and Extreme Spread of Velocity Questi

Postby The German » Sun Jan 22, 2017 6:06 pm

If you treat the plastic parts by dipping them into water with some more dish soap in it than you would use to clean your dishes and let them air dry (don't wipe dry), the static will be gone for a long time. When needed, repeat...
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Re: Powder Measurement and Extreme Spread of Velocity Questi

Postby Morne » Mon Jan 23, 2017 11:12 pm

I've given this a lot of thought. My chrono data collection has been EXTENSIVE of late. I, too, have seen some disconcerting Extreme Spreads (ES) and done more than my fair share of head scratching.

Like the OP, my initial thought was, "I'm throwing powder inconsistently and/or my scale sucks." But after experimenting with different scales I've reached the conclusion that good powder throw habits (like always tapping after dispensation to ensure everything comes out) make my Lee Auto Drum pretty consistent. In fact, it'll throw more consistently than my scale will weigh it - so I've learned to STOP "chasing throw weights" with constant adjustments to the LAD while loading a batch.

But that still doesn't account for some of the differences. Take this example of the same bullet fired with the same charge weight of powder through the same 2 guns...only parameter varied was the primer (and maybe the COAL but that doesn't much matter for a cartridge with all the space of a .38 Special):

COAL__________Trail Boss Powder____125-gr Lead RNFP bullet____________________Barrel
Inches:_________Grains:____________Avg. Velocity:___________ES:___Primer:______Inches:
1.369-1.393_____3.7_______________762______________________49____FED-100 SPP__5.5
1.369-1.393_____3.7_______________967______________________40.4__FED-100 SPP__20
1.440-1.448_____3.7_______________775______________________112.1_REM 1.5 SPP___5.5
1.440-1.448_____3.7_______________974______________________91.4__REM 1.5 SPP___20

Thus, CLEARLY the FED-100 primer gives tighter ES values. That has to be a factor.

Then I hypothesized that, "Maybe each gun's throat or cylinder gap caused the ES to be measured from it to be tighter or looser." But some thorough review showed that to be wrong, as this .44 Mag load data shows:

COAL__________Lil' gun Powder______240-gr X-Treme CPFP bullet________________________Barrel
Inches:_________Grains:____________Avg. Velocity:_____________ES:____Primer:__________Inches:
1.574-1.583_____16_________________1031_____________________96.8___CCI-350 LPP(m)____6.5
1.565-1.576_____17_________________963______________________9.9____CCI-350 LPP(m)____4
1.565-1.576_____17_________________1066_____________________135____CCI-350 LPP(m)____6.5
1.569-1.573_____18.1_______________1019______________________28____CCI-350 LPP(m)____4
1.569-1.573_____18.1_______________1112______________________70____CCI-350 LPP(m)____6.5
1.567-1.577_____19_________________1083______________________93____CCI-350 LPP(m)____4
1.567-1.577_____19_________________1195______________________69____CCI-350 LPP(m)____6.5
1.575-1.587_____19.6_______________1138______________________47____CCI-350 LPP(m)____4
1.575-1.587_____19.6_______________1287______________________36____CCI-350 LPP(m)____6.5

See how the 17-gr load is tightest in the 4" gun but loosest in the 6.5" gun? Then see how the tightest for the 6.5" is the 19.6-gr load which is one of the looser data sets for the 4" gun. I have other data that seems to indicate one gun is always tighter in ES than another...and then I collect new data that refutes that assertion.

So what does all this mean? A lot, and very little, all at the same time.

It means there are a LOT of parameters that go into ES. Furthermore, it shows that ES is just a thumbnail and NOT statistically significant. So what's it good for? Getting an IDEA for a decent load...nothing more.

After you get an IDEA then you need to put a statistically significant number of rounds over the chrono and see how the standard deviation (SD) pans out. I'm talking over 20 data points here.

I'm about to start doing just that, with .500 S&W Magnum rounds no less. :shock:
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Re: Powder Measurement and Extreme Spread of Velocity Questi

Postby Sevens » Tue Jan 24, 2017 3:47 pm

I would like to add that you may wish to be careful about SOME seemingly good conclusions. For example... you can point to a primer being the big difference maker in a load and that is hard to argue, but if you were to also test a totally different powder, you might find that an array of different primers have very little effect in that particular load.

Also, you have to think that the idea expressed above about different chambers in a revolver spitting out different results is also quite possible. The best "real world" useful chrono work would be with whatever firearm you intend to use the loads in... but if all you wish to nail down is the load itself, a single shot shot such a T/C Contender could be a phenomenal platform for doing the legwork long before introducing a new possible pet load to your working guns.

I find... and you may also be finding... that the more we think we learn, the more we find there is yet to be discovered. And the $%&#$%$*'ing chronograph seems to offer help and wisdom but we simply have to remember that if just one little bit goes wrong, it will make the entire string look like total hell. So you honestly have to ask yourself and try to keep your hopes, wants and dreams out of it... but when you are clocking those loads and one of them goes full retard, was it a chrono blip or did you really indeed have a crappy handload? If it was a crappy handload, was that some internal ballistics black magic having to do with space, gas expansion and a litany of other things I sure don't understand? Or did you muff a powder drop? Did you have a primer that just didn't flame up well or a poorly drilled flash hole in your brass?

Obviously, this is why your statement about -many- data points is obviously key and it's what I've said for a long time.

If I do 10 shots and they look good, I don't want to go home and roll 500 rounds. What I really want to do is put 30 shots of the load over the chrono and see 30 fantastic shots, that's what I want.
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Re: Powder Measurement and Extreme Spread of Velocity Questi

Postby Mr. Glock » Tue Jan 24, 2017 5:17 pm

I love my chrono...been collecting data on literally a couple-few hundred factory loads for a few years. What can I say, I'm a nerd.

But, point well taken for reloading. I'm really just looking for a decent load that I can shoot in any 38 or 44 because I know it is consistent enough to be safe. I figure if a regular 38 load runs 100 fps or under in extreme spread, that's a good load in terms of safety. What I don't want is super-low fps rounds or way too high fps round being randomly added to the mix. Consistency is what I'm after, and it does have an acceptable range.

Best shooting load etc, that's a different matter. And I'm not there yet.

To add, I did dig up some old chrono data where i shot the 6" gun I was using in this thread with another gun, and the 6" showed about double the ES than the other gun. However, the other gun was also a snubbie 5 shot, and so the 6" was being loaded with 5 rounds only. In one case, the 6" actually had a lower ES. One case out of seven different loads (all 357). Doesn't prove anything, but does point to something. When I get the chance, I might just do strings out of each cylinder...would be interesting to me. It is a very accurate gun overall.
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Re: Powder Measurement and Extreme Spread of Velocity Questi

Postby Morne » Wed Jan 25, 2017 9:53 am

Trail Boss powder driving a light (for caliber) lead slug is probably the safest you'll find for either .38 Spl or .44 Spl. Lots of cowboy shooter data running around. I've developed some of my own .38 Spl loads with this combination as detailed elsewhere hereon.

Stop on down sometime and we'll do some shooting. :idea:
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Re: Powder Measurement and Extreme Spread of Velocity Questi

Postby Mr. Glock » Wed Jan 25, 2017 10:00 am

Gotta wait until it is really cold or really hot, seems like that is the only time we shoot. :mrgreen:

Moving to the new powders took care of the safety issue, they drop consistently.
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Re: Powder Measurement and Extreme Spread of Velocity Questi

Postby Sevens » Wed Jan 25, 2017 3:42 pm

Just because it seems relevant...

For many many decades, legions of handgun reloaders stocked basically three powders, all from Hercules. Ordered fast burning to slower, it was Bullseye, Unique and 2400. When you wanted target .38 or .45, you used Bullseye. When you wanted heavier .38 or mid-range magnum stuff, Unique was simply unbeatable and 2400 was the juice when you wanted everything you could get from a heavy magnum handload. Elmer Keith developed the .44 Mag in the 1950's using 2400 powder and I wouldn't be too surprised if Dick Casull did the same thing in the 1960's along the way with .454 Casull.

The chrono was a toy for scientists or only the guys with a lot of money to throw at the hobby and the earliest chronographs were hilarious in use compared to what we use today. But truckloads of great handloads were made with these three powders, a load manual or two, no chrono and quite often -- a powder dipper. Those tools were more than enough and the ammo was good enough for the task.

I'm not trying to rail against progress (dangit, I'm not that old!) but I think a lot of us introduce "problems" with a chrono nearly as often as we seemingly solve them. I can admit for sure that I never really gave a damn about how fast I could push a particular bullet until I got a hold of a device that reported the speed of that bullet. I've found myself chasing velocity on occasion for no tangible reason other than adding the information to my collecion of data. Now that isn't a bad reason at all, especially if the chase is smart, safe and enjoyable, but before the fun-sucker came in to my life... it just really didn't matter to me.
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