Load Variation in a Dillon

[metallurgist]

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.

That seems pretty good, especially compared to what I measured. I'm +/- 0.006 across everything. About 70% of mine is +/- 0.002 with the rest outside.

I'm curious, do you have anything special with your setup? Such as, what die are you sizing with, does the die have a rubber o-ring, etc?

 

[BDman]

I've used both the Dillon toolheads and the Whidden's and see no difference. I've used Whidden, Forster and Redding dies with and without O rings and see no difference in sizing except for runout. The O rings seem to help that with the factory toolhead (the Whidden floats) and I get less than .001.

 

[David Christian]

Don’t know if this is helpful, but during covid I switched from a single stage press to a Dillon 750 and encountered several items where I needed to fine tune the progressive press for precision reloading.

I cleaned up my tolerances to .0015 max ES with most being within .0005 for both sizing and seating by doing 2 main things. Honed the shell plate, and also installed a thrust bearing. Both of these steps allowed me to tighten the center bolt considerable while still allowing the shell plate to rotate smoothly. I removed a ton of slop.

Here are some pics.

blued the bottom with a sharpie first:

then I reinstalled it as tight as possible to put pressure on the high spots to identify where I needed to hone.


Here is the thrust bearing and location of install:

 

[jonbearman]

If I remember correctly you cant use stick powder unless it cuts with ease. 4895,3031,4350 etc and 4831 just as an example I would use a scale and just use the machine to prep. Then you can seat them all on the machine. I use an old rcbs thrower and a scot parker tuned scale. I tried extruded powder once and weighing them was all over the place. Maybe I am doing something wrong for all I know.

 

[Doug30racer]

not sure if anyone has said this, but make sure the loader is GROUNDED. On a progressive shotshell loader in the past it was very easy to get static buildup in the powder tube. It made a big sd difference over the crony.

 

[Mr Underbridge]

Precision ammo on a progressive loader?! Im scandalized

 

[powderbrake]

Precision ammo on a progressive loader?! Im scandalized

I have a friend who is a top level High Power shooter, President's 100 and all that, and he does all his loading on a Dillon 1050 to gain those rankings.

 

[metallurgist]

Finally getting to the live-fired velocity results.

Video starts a little slow, so bear with me as I worked through the background.

Overall, I definitely need to be getting the powder drops dialed in. That variation was so large that it was difficult to see effects from the other factors.

My standard deviation of my powder drops was still in the 0.17-0.18 grains range, and my test showed about 5-6 fps difference per 0.1 grains.

My extreme spread is in the 63-70 feet per second range. I'd like to cut that in half at a minimum for now.

My goal right now is to get my SD to less than 0.1 grains. If I can get that dialed in, I'll move on to the next pieces.

 

[BDman]

I think your numbers are pretty close. Polish that powder measure and try it again. Powder volume/drops used to be the way BR shooters did it but not so much anymore. There are so many other variables to measure - case volume, NT, primer depth, bullet weight/ogive length etc. If powder charge is close on a good node, the paper results will be negligible at 100 yds. It will show up at extended distance.

If you polish that measure and get it down to +/- .1 or .2 in a stable node you'll get those ES's cut in half. If I "bulk" load .308's or others with the polished measure, I'll get an ES of 25-30 and SD of 15 or so. It's fine out to 600 yards. With any true accuracy loads I weigh charges. Just my .02...

Edit: If you're not on a "node" for your barrel, you'll see terrible ES and SD numbers with miniscule powder changes making huge variations. My other .02...

 

[Twdmar]

The precision of the dillon measure is plenty good for shooting highpower targets. There are ways to improve consistency.
Polish the powder funnels, the inside of the measure and powder bars to improve flow. Use a second powder baffle and make sure the fail safe rod pulls the powder bar out completely.
I keep my measure full and clamp an aquarium bubbler to the powder hopper to keep the powder settled down. How you run the handle seems to make a difference too.
The dillon is a great machine but some tweaks do help.

 

[jelenko]

Use a second powder baffle

Did you happen to test the effect of the second baffle? Where did you place it? I.e., how far for the built in one?

 

[Hoser]

Precision ammo on a progressive loader?! Im scandalized

All the way up to 338 Lapua on my 550s. Not using the Dillon measure though.

 

[dcali]

I've never had any luck with any powder measure with any extruded powder (at least, not by the standards that long range shooters demand today). I don't think it's possible to get there, to be honest. The better way to skin this cat is just to use an automatic tickler (autotrickler, RCBS, etc) and manually charge with a funnel in place of the powder measure. Or find a ball powder that meets your needs (easier said than done, if 0.05 grains of powder matters to you).

 

[Mr Underbridge]

All the way up to 338 Lapua on my 550s. Not using the Dillon measure though.

I see that 550 is popular here, why not a 650?

 

[metallurgist]

I think your numbers are pretty close. Polish that powder measure and try it again. Powder volume/drops used to be the way BR shooters did it but not so much anymore. There are so many other variables to measure - case volume, NT, primer depth, bullet weight/ogive length etc. If powder charge is close on a good node, the paper results will be negligible at 100 yds. It will show up at extended distance.

If you polish that measure and get it down to +/- .1 or .2 in a stable node you'll get those ES's cut in half. If I "bulk" load .308's or others with the polished measure, I'll get an ES of 25-30 and SD of 15 or so. It's fine out to 600 yards. With any true accuracy loads I weigh charges. Just my .02...

Edit: If you're not on a "node" for your barrel, you'll see terrible ES and SD numbers with miniscule powder changes making huge variations. My other .02...

That makes me happy to hear you say that. I've been a little worried that I won't be able to make an improvement, but it looks like it'll be an option after all.

 

[metallurgist]

Did you happen to test the effect of the second baffle? Where did you place it? I.e., how far for the built in one?

I'm in the process of testing that right now. I'm hoping to have some results in the next few days. First attempt was "no," but I'm making a couple other tweaks based on suggestions to see if there's any improvement.

 

[metallurgist]

All the way up to 338 Lapua on my 550s. Not using the Dillon measure though.

Man, that's a nice setup. I have already put an A&D down on my wishlist. Far cry from my Frankford Arsenal pocket scale lol

 

[JayHHI6818]

Polish that powder measure and try it again.

What are you using to polish Dillon powder measure?

Thx

 

[Twdmar]

Did you happen to test the effect of the second baffle? Where did you place it? I.e., how far for the built in one?

The add on sits about an inch above the other, I dont remember if I tested before and after. My theory is that the powder column at the bottom is less variable based on how much powder is in the measure. I can say that on paper it works well. At 600 yds with a 223 service rifle, ar-comp thrown charges made a .3 moa height group with a sling according to my silver mountain.
But I also have an auto trickle for LR too.

 

[atblis]

Have you done some design of experiments excercises for this effort?