Metering Blue Dot

[meshugunner]

I'm loading .357 mag with about 10gn Blue Dot and having a helluva time getting consistent charges. So far I have developed the following voodoo.

1. Make sure all your cases bell even if you dont really need it. This ensures a complete stroke of the powder bar.

2. Shake the powder holder to settle the powder.

3. Rattle the powder measure before every throw.

4. Tongue on the left side with light pressure from the molars.

This gets me down to +/- .1 gn MOSTly. But it's fiddlyl tricky and not really reliable.

Does anyone have tips or techniques for this? I there something I can do to improve the powder measure itself?

Thanks for any help.

[Desmo412]

My only advice would be to buy a Hornady powder measure. I have yet to find a powder that won't hold +-0.1gr. It is a simple design that just works really well. They are case-activated....you could install one in any press

[TheChimp]

Huh, I just started loading 10mm using Blue Dot, and I felt it was pretty consistent. With sampling every 15-20 rounds and loading about 200, my charge weight didn't vary by more than .1 gr on any sampled rounds. ALL were less than .1 off.

Is your powder measure smoothed and polished? Mine is like a mirror inside. Funny, I was thinking how much I like Blue Dot, and how decently it measured.

Good luck!

Ken

[SD1]

Easy quick checks....

1 calibrate scale first and test.

2 verify bellcrank cube is traveling Stop to stop, with NO GAPS

[meshugunner]

Thanks for the advice guys.

The scale agrees with my balance beam.

What parts should I polish? Just the powder bar or should I do every surface that the powder contacts?

I'll look into the Hornady powder measure.

I shot my reloads today. About half the cases had flattened primers and about 1/4 were sticky to extract. These were supposed to be midrange .357 charges. I must be throwing wilder charges than I hoped. I can back off the charges but unless I get acceptable consistency I have no hope of accuracy.

[tunaman]

Look into adding a baffle to the powder measure also... I've seen several reports that this cures alot of measure issues.

[SD1]

I have a Hornady Ammo Plant and a 1050.

They both meter accurately.

I think you just need to tear down measure and clean out with alcohol.

[meshugunner]

Yah, I will give it a work over today. Some polishing, some powdered graphite is supposed to help lubricate things. There is also the possibility that static is an issue - it's extremely dry here in the desert SW USA. Dryer sheets and a ground strap might help with that. A baffle seems worth a try. I have a plan to make one out of a small plastic funnel cut to size. I'll also ensure that the slide goes from stop to stop.

The Hornady powder measure is $80. I'm reluctant to spend that much although a second measure would be convenient for swapping back and forth. Does it work with the Dillon powder funnel? If not, how do I bell the cases?

Thanks.

[SD1]

They have a PTX also with the LNL.

I dont think you need it. Spend money on something else.

The Dillon is quicker to set up between caliber changes.

Btw How many rounds threw the powder measure?

Blue and Red seem to get more accurate around 800-1000 drops.

Metering about 200 grains of Graphite is a Old School trick that supposedly helps as you stated

My Gramps taught me that one

[meshugunner]

Well I did all the above plus I rinsed the plastic hopper with soapy water and removed the linkage and wrapped a couple of rubber bands around the hopper and over the powder bar for a more positive return stroke. I am now getting 12.9gn +/- 1gn with an occaisonal flyer of +/- 2gn. Which is a big improvement. I should have done these refinements one at a time to see what difference each one made but I didn't feel like reassembling the whole shebang and running test measurements 10 times. I would like to eliminate the flyers but they are tolerable. This and testing took quite a bit of time. Still if it means my powders meter more reliably I'm happy.

Tomorrow I will crank out some reloads and see what the spread is on the chronograph. I wasn't able to do that with the last batch since I didn't have the chronograph but judging from other evidence, I think my loads were pretty wild.

Thanks for all the advice.

Edited March 23, 2013 by meshugunner

[meshugunner]

For the sake of closure, I went down to the range with another set of loads to try them out in my BlackHawk 6.5" bbl

All numbers are in fps. Bullets cast from wheel weights.

Group #1 148gn WC tumble lube 8.6gns BlueDot

1311

1295

1277

1326

1320

Group #2 148gn WC tumble lube 9.0gns BlueDot

1357

1337

1371

1349

1363

1256

Group #3 105gn SWC tumble lube 9.0gns BlueDot

1346

1359

1287

1304

1242

1097 ??

These velocities were about 200 fps faster than the load data suggested, but that was for a 4" bbl.

I don't understand why the 105 SWCs weren't moving faster than the 148's with about the same powder charge. Also, even ignoring the one outlier @1097 they have a wider spread than the heavier bullets.

The 148's leaded horribly on the 2nd half of the bbl. I guess tumble lube isn't up to this kind of velocity. I will switch to grease grooves.

Shot some paper freehand @10yds and they all printed about 1.5" excluding fliers which I attribute to operator incompetency. Later I will try them from a rest to get a better idea of what the gun & ammo are doing.

They were all very comfortable to shoot. I could have shot all day - but the BH is a big chunk of iron. Primers were flattened but still retained their dimples. Cases slid out easily but mostly didn't fall out. They showed no signs of bulging.

I didn't really mean to load this hot. I selected loads near the min suggested in the manuals and the velocities seem about right allowing for the extra bbl length. I'm wondering if I should switch from small mag to small pistol primers.

Anyway, this is whole different set of problems and I am much happier fiddling with load parameters than having to struggle with random powder charges.

All this trial and error has used up about 1/2 my pound of Blue Dot. I think I will try 2400 or H110 when I finish this batch, but I might come back to the BD and it's nice to know I can if I want to.

Again, thanks.