Load Variation in a Dillon

[metallurgist]

I've discussed the variation of loads in a Dillon with a couple friends lately. That got me to wondering about testing just how much mine vary.

Then in perfect timing, one of the articles in Dillon Precision's latest catalog was explaining a test they performed on comparing powder charge weights from their powder measure to other methods.

I decided that I'm going to put together a series of 3 different tests looking at the variation in powder, case sizing, seating, etc., and how that relates to performance.

This is the first test which is about powder charges, and I'll update as I complete the other two. I compared some of Dillon's data to my own in the video, and I made an attempt to translate that into variations in POI based on powder only.

Overall: I saw higher variation in my powder drops than Dillon did, 0.17 grains standard deviation vs Dillon's 0.11 grains.

Updating for easier navigation:

I have also now tested 100 rounds for variations in my headspace after sizing in my Dillon and looked at the variation in sized/trimmed/deburred brass weight (Winchester brass).

Headspace standard deviation was wayy more than what I wanted at about 0.002" variation.

Brass weight standard deviation was about what I expected at about 1.2 grains, so weight sorting should have a small impact.

Update #2:

Live fired velocity results!

I'm seeing about 5-6 feet per second difference in velocity per 0.1 grains difference in powder. With a standard deviation currently of 0.17-0.18 grains, I need to get that dialed in. My extreme spreads are in the 63-70 feet per second range. Overall length and brass weight potentially have some effect. Bullet weight and headspace don't seem to be having a noticeable impact.

 

[atblis]

How many charges did you throw and measure to come up with your 0.17 gr SD? How many did Dillon use to come up with theirs?

 

[NZ_Fclass]

My ad hoc testing with a 550 and loading 38 special for ISSF shooting showed that powder type made a lot of difference. Eventually I settled on HP 38 which metered best. When testing I would throw around 30 loads, of every suitable powder I could get hold of.weighing on an RCBS 1010 and just watching for variation. Would I use a powder measure for rifle loading? Not really, never happy with results and the odd pile of powder falling out when dropping the ram!

 

[Zero333]

I load thousands of 9mm Luger with Titegroup every year on my 650 and this powder meters so precisely it's unbelievable. But you need to drop a dozen charges that get it right on and stop the variation and have to keep the hopper full.

Also load tons of 308 with w748, and it's variation is not bad at all either. But the rifle stick powders don't fare so well.. h4895 can vary 1 tenth up or down, with the occasional 2 tenths over or under.

 

[shortgrass]

Ball powders meter best, flake pretty good, but extruded not at all. Just my experience..

 

[Zero333]

I've discussed the variation of loads in a Dillon with a couple friends lately. That got me to wondering about testing just how much mine vary.

Then in perfect timing, one of the articles in Dillon Precision's latest catalog was explaining a test they performed on comparing powder charge weights from their powder measure to other methods.

I decided that I'm going to put together a series of 3 different tests looking at the variation in powder, case sizing, seating, etc., and how that relates to performance.

This is the first test which is about powder charges, and I'll update as I complete the other two. I compared some of Dillon's data to my own in the video, and I made an attempt to translate that into variations in POI based on powder only.

Overall: I saw higher variation in my powder drops than Dillon did, 0.17 grains standard deviation vs Dillon's 0.11 grains.

I assume the higher weights did not start till a little into the test. That's because as you run the press the vibration shakes and packs the kernels a little tighter.

Best is to have a full hopper and tap it all over with some plastic or wood and watch the kernels settle. Then as you start dropping you'll still have to adjust for at least a couple dozen or more throws before it becomes more consistent.

This is true for all types of powders, be they ball, flake or stick.

 

[jelenko]

When I first started using a Dillon 550B, I would drop and weigh 25 loads of various powders to see what the variation was. The loads were all for 308 or 223. I only looked for extreme spread.

With ball or flake powders, I've found the vast majority were +/- .15 grs. 1 or 2 out of 25 would be off by .2 in either + or minus.
With the targets in 'across the course' competition, this variation is fine for out to 300 yards. For 600 yards, there are many who feel this is also fine - many also feel it's important to weigh each charge.

For me, long grain extruded powders were a no go. Others have reported success with minor mods to the powder funnel.

These days I'm using 8208 which seems to meter about the same as ball or flake. For prone slow at 300 yards or longer I do weigh each charge - just because and it's only 22 rounds.

 

[BDman]

After polishing my powder measure funnel and bar, I get +/- .1 grains (occasionally .2 over/under) with Varget and H4350. That still gives me roughly half moa or better to 600 yards which is plenty good for most steel target ranges. SD's are in the teens and ES mid 30's. For load development/paper or longer distance, I measure with a V3. SD's are single digit and ES in the teens or lower. JME.

 

[memilanuk]

Overall: I saw higher variation in my powder drops than Dillon did

Glad to know I'm not the only one.

When I saw that article on the cover, I was a little excited, I'll admit.

A little less so when I found that it was simply (so far) a test of the powder measure(s).

Even less when I noted that their results were a *lot* more optimistic than mine. Granted, I don't have my test notes from that time frame any more, but the short version of what I remember was that the Dillon APM wasn't even within shouting distance of the Uniflow, or a Lee APM for that matter, when it came to Varget or RE-15. And while the variance of the Uniflow was actually acceptable for what my intended purpose was at the time (short yardline ammo for NRA XTC) I'd have reservations about using it on an MR-1 target, much less anything requiring more precision.

 

[powderbrake]

Re Dillon measures;
About 5 years ago, a friend of mine said that the RCBS Uniflow with auto actuate on a Dillon was better than the Dillon measure, so I decided to test it.
I threw 45 loads of Varget at 31.7 gr from each measure while it was mounted on the 550. Here are the results, measured with a PACT digital powder scale that reads to 0.1.

Dillon
Ave 31.71458
Max 31.9
Min 31.4
SD 0.107992

Note an ES of 0.5

RCBS Uniflow
Ave 31.69375
Max 32
Min 31.4
SD 0.137547

Note an ES of 0.6

As it turns out, the Dillon was better, although neither was very good. I say better because of ES, which I consider to be the definitive attribute of a powder dispensing system. Why is that?

1) All powder measures throw very close to the setpoint or average. The more you test the closer they get.

BUT

2) Good groups or competitive scores depend on EACH INDIVIDUAL POWDER CHARGE being the same. Averages thrown don't mean squat to 5 or 10 shot groups. That is why the best on target results come with the smallest extreme spread of powder weight.

I am not knocking the Dillon or RCBS measures. I have about 10 Dillon measures mounted on 550 heads for various rifle and some pistol calibers. (Although for small charges like 2.8 gr Bullseye, I use the Lee Pro Disk on the Dillon 550) For serious rifle accuracy, I use a Fx120i with Auto throw and Auto trickler.

No, I have not retested since I acquired my much better scale.
I like BDman's idea of polishing the funnel and bar. if I got his +_ .2, it would be a 20% increase in accuracy of the throws on the Dillon.

 

[Rsadams]

If the Dillon is setup and operated correctly it works and powder drops very well right out of the box... If you're trying to cram a bunch of rounds per minute through it it can move around some but that's normally created by the operator... Just like the uniflow the handle has to be operated at the same speed etc to get the best results... The uniflow is accurate but you have to raise and lower the handle at basically the same speed every time which is just easier to do with the Dillon in my opinion.... I have absolutely never regretted buying my Dillon only wish I would have done so sooner... It is a great setup...

 

[metallurgist]

I must not have had my notification settings set right for this thread because I didn't know everyone was responding!

Thanks for all the added input. I'm glad to know that I'm not the only one here with the issues.

To answer a few questions I noticed:
- @atblis My test was from 100 powder throws. Dillon only did 30 in their test in the magazine.
- @Zero333 Yes, I set my powder early and didn't touch it. I think you're spot on with it packing down and causing the average to end up higher than what I ran my set-point tests at.
- @powderbrake Spot on! Yes, an average is an average, so if all 5 powders are all over your range of standard deviation, then you won't have the consistency you're after compared to if all loads were loaded exactly to the average.

Updating here:

I also wanted to test my headspace variation in addition to brass weights before I get into the live fire with real velocity data so that I can try to bring them all together and see what does what.

I had wayy more variation in headspace than I expected. A standard deviation of about 0.002" on that. I'm going to have to dive into that some more.

Brass weights varied how I expected. Theoretical variations show some potential for varying velocities from brass weight.

This video is my results. Next video will have velocity data, then I'll get back to seeing if I can reduce the powder variation.

 

[BDman]

Winchester brass is not the best from a consistency standpoint. Better quality brass always gives me more consistent HS when sizing. The higher end brass seems to have a more consistent "feel" when sizing and "look" when annealing and very few with the wild HS variance that seems to occur fairly often with less expensive brass. With quality brass, the Dillon will size as accurately as anything out there - it can vary if you change which stations have a piece of brass in them. I do my sizing as a single step when loading precision rifle ammo. JMHO

 

[Oso]

As mentioned above the type of powder (ball, flake, and extruded rod) makes a big difference. When loading for high precision then hand loading is best (each charge weighed). The trade-off with a progressive press is rate of reloading efficiency vs. mechanical precision. A progressive press is great for pistol and has no problem achieving 1moa rifle. If you want more control then you need less moving parts, which translates into a manual process that is slower.

Another consideration is Gravity... more downward force when powder tube is full. This force way impact the amount of powder forced out/thrown when tube is full versus empty. To address this issue there are some aftermarket powder baffles that keep the amount of pressure on powder at the thrower consistent regardless of amount of powder in the powder tube/hopper. They are relatively inexpensive upgrades that simply drop inside the powder tube.

 

[nicholst55]

I read several years ago that the Dillon machines size more consistently with all stations filled with a case or loaded round. This prevents the shell plate tipping as it is raised. I must confess that I have never performed any testing to verify this, but I believe it to be true. I can see the tilt of the shell plate if I watch closely when there is only one case in place.

 

[metallurgist]

Winchester brass is not the best from a consistency standpoint. Better quality brass always gives me more consistent HS when sizing. The higher end brass seems to have a more consistent "feel" when sizing and "look" when annealing and very few with the wild HS variance that seems to occur fairly often with less expensive brass. With quality brass, the Dillon will size as accurately as anything out there - it can vary if you change which stations have a piece of brass in them. I do my sizing as a single step when loading precision rifle ammo. JMHO

Interesting, thank you. I know Winchester isn't top of the line, but I figured it would probably be a little better than military surplus brass, too. What kind of consistency in HS do you typically look for?

 

[metallurgist]

As mentioned above the type of powder (ball, flake, and extruded rod) makes a big difference. When loading for high precision then hand loading is best (each charge weighed). The trade-off with a progressive press is rate of reloading efficiency vs. mechanical precision. A progressive press is great for pistol and has no problem achieving 1moa rifle. If you want more control then you need less moving parts, which translates into a manual process that is slower.

Another consideration is Gravity... more downward force when powder tube is full. This force way impact the amount of powder forced out/thrown when tube is full versus empty. To address this issue there are some aftermarket powder baffles that keep the amount of pressure on powder at the thrower consistent regardless of amount of powder in the powder tube/hopper. They are relatively inexpensive upgrades that simply drop inside the powder tube.

A powder baffle is consistently coming up as one of the top recommendations, so I'm definitely going to try that out!

I was talking to a friend in manufacturing who made particulate masks (very critical fill rate also), and he gave me some ideas as well. One he mentioned was "fall height" which would speak to how much the powder is packing...which is what the baffle is addressing.

 

[metallurgist]

I read several years ago that the Dillon machines size more consistently with all stations filled with a case or loaded round. This prevents the shell plate tipping as it is raised. I must confess that I have never performed any testing to verify this, but I believe it to be true. I can see the tilt of the shell plate if I watch closely when there is only one case in place.

So I noticed my toolhead moving without any brass in it. When looking closer, the center bolt that holds the shellplate down is contacting the center hole of the toolhead. I don't know if it's just a poor setup on my part, but the chamfer on the bolt head and the hole in the toolhead seem like it was designed so that the bolt would push the toolhead to the top of the groove in the press. I did see somewhere that they made a threaded insert and bolt kit to replace the pins and keep the toolhead to the top.

 

[Oso]

A powder baffle is consistently coming up as one of the top recommendations, so I'm definitely going to try that out!

I was talking to a friend in manufacturing who made particulate masks (very critical fill rate also), and he gave me some ideas as well. One he mentioned was "fall height" which would speak to how much the powder is packing...which is what the baffle is addressing.

I just bought one for my 1050.... small price so why not. There are plenty of options on Amazon or wherever you like shopping. It's a small metal plate that sits above the powder funnel in the powder tube. It has several holes to allow powder to easily flow through to the powder funnel at consistent rate, while at same time it bears the weight of powder that is sitting above it in powder tube.

 

[BDman]

Interesting, thank you. I know Winchester isn't top of the line, but I figured it would probably be a little better than military surplus brass, too. What kind of consistency in HS do you typically look for?

When using good quality brass (Lapua, Peterson etc.) I can maintain +/- .0005 with about 85% of the cases. About 15 out of 100 will be the ones that size differently.001-.002 from the norm. With cheaper brass that % goes up to around 25-30% and out by as much as .003. Friends using coax and single stages tell me they experience the same.

If the shell plate is reasonably tightened it seems to make little difference. As long as the base of the case is allowed to sit fully on the platform of the ram as it has zero flex. When other stations have cases in them, it does slightly change how firmly the case base makes contact with the platform due to some shell plate interference. However, that difference is constant if the stations are filled with brass; if not, you'll see about .001-.0015 variation. As I stated previously, I do my sizing as a separate step to avoid that variable.

Edit: The toolhead floats as it is and I get less RO using the factory setup than a friend who tried locking his toolhead. He switched back. Runout from factory is .001 max and rare. The locked toolhead was giving .001-.002 regularly.