Bullseye density changed?


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DaveBeal
March 6, 2010, 10:30 PM
I've been reloading for about six months, using a Lee Classic Cast single-stage and Lee AutoDisk powder dispenser. Loading for 9mm and .45ACP, I recently finished my first pound of Bullseye and bought a second. I had been using the 0.43cc cavity of the AutoDisk to drop 3.9 to 4.0 grains. With the second bottle of Bullseye, this same cavity is throwing only 3.7 to 3.8 grains; I had to move up to the 0.46cc cavity to get 4.0 grains. Is it possible that the density of Bullseye could change by 5 to 10 percent between lots? I've taken the AutoDisk apart a couple times and found no problems or obstructions. I thought maybe it was a static problem (Colorado air is pretty dry this time of year), so I wiped all the parts with a dryer sheet, but nothing changed.

I know that Bullseye has been in production for decades, so it seems unlikely that it would change from lot to lot. Should I be looking elsewhere for a explanation?

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ReloaderFred
March 6, 2010, 10:43 PM
I haven't experienced any change in Bullseye over the years. I normally buy it in 32 pound cases, though, and very seldom buy a one pound container of any powder, unless I just want to try something new. I've been using Bullseye pretty regularly for about 40 years or so, and it meters just like it always did for me.

Whenever I pour powder in the hopper, I throw anywhere from ten to twenty charges to get the powder settled before I weigh for the charging of the cases. There can be a difference between freshly poured powder and that which has settled and somewhat compacted.

Hope this helps.

Fred

bds
March 6, 2010, 10:46 PM
Just mix what's left of the old powder with the new powder well.

Weigh several charges and bingo, no problem.

1SOW
March 6, 2010, 10:51 PM
My Lee Auto-Disc does the same for the first 6 or 8 throws after a new fill, then it settles in to specs.

You can also use a dowell to tap it a few times to insure the disc is full.

Sunray
March 6, 2010, 10:57 PM
Throw the scoops away and use a scale. The scoops can vary the charge plus or minus a full grain. What possessed Lee to calibrate 'em in CC's, in the first place, is beyond me. CC's are a metric volume measurement. Nothing whatever to do with smokeless gun powder.

SlamFire1
March 7, 2010, 10:11 AM
Is it possible that the density of Bullseye could change by 5 to 10 percent between lots?

Yes. The powders we use are blended to give a consistant burn rate and pressure curve by weight. Other characteristics such as density, volume, color, smell, are not as critical.

rcmodel
March 7, 2010, 11:34 AM
Yes, it's possible, but most of use would never know it if it did change volume.

Because we use scales and adjustable powder measures.
It is not uncommon to have to re-set a powder measure when changing to a new can of the same powder.

A fixed volume dipper or disk is at the mercy of the powder gods to make every single can of powder ever made exactly the same fluffyness.

And it just ain't gonna happen.

rc

rjbishop
March 7, 2010, 11:51 AM
Throw the scoops away and use a scale. The scoops can vary the charge plus or minus a full grain. What possessed Lee to calibrate 'em in CC's, in the first place, is beyond me. CC's are a metric volume measurement. Nothing whatever to do with smokeless gun powder.
The original post said nothing about dippers- the auto-disk was being used. That said, they are VERY accurate, and certainly don't vary by 1 grain. I also can tell you that the dippers do NOT vary 1 grain- I don't know where you get that.

How would you have Lee calibrate the dippers? They are strictly a measure of volume, that's it. So you think something like cubic inches would be better? Teaspoons? You sure won't get it in grains, as obviously that depends on what powder you are using.

Peter M. Eick
March 7, 2010, 12:49 PM
Your first can the solvents dried out and it lost some moisture. The second can is newer and has not dried out yet. I see that when I have bought several can's from the same load of like 2400. When I set up the measure for the current powder which is the opened can, then switch to a new can from the same lot, it almost always is heavier. Same thing with 4227.

When I switch AA9 to a new can today I will see the same thing I am sure.

For this reason I am trying to move to 4 or 8 lb cans of powder and not have so many changes.

mbopp
March 7, 2010, 02:01 PM
I had some 20 year old Bullseye and also bought a new can. Using the pistol insert in my Redding measure the new powder is more dense ie throws a heavier charge than the old can on a given setting.

ramduster
March 8, 2010, 10:34 AM
First I would like to say hello to everyone as this is my first post and also ask are you using the .43cc cavity for both 9mm and 45acp.

Grump
March 8, 2010, 08:10 PM
I get minor density changes with several different powders.

My suspicion is that blending for density is part of how the makers/marketers blend cannister-grade powders to (usually) perform the same with the same charge WEIGHT through the years.

IIRC, an article on the then-"new" Unique powder compared it to a sealed jug of "old" stuff more than 20 years old. Velocities between the two were within the error range of the chronograph, and well within the expected range of sample variations if NOT using different lots of powder. If not identical, the density was very, very, close.

DaveBeal
March 9, 2010, 08:20 PM
My thanks to everyone who responded. While it may not explain the change from one bottle to the next, the idea of the powder settling and becoming more dense as it sits in the hopper is helpful. I had noticed this effect and this explanation hadn't occurred to me.

First I would like to say hello to everyone as this is my first post and also ask are you using the .43cc cavity for both 9mm and 45acp.

Yes, I was.

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