Load size: Better to go slightly under or over?


May 21, 2010, 07:56 PM
Hey guys, I've been using the Lee Pro AutoDisk powder measure.

I'm loading 200 grain lead RNFP in .45acp with Bullseye. The Lee reloading manual gave the starting and max loads at 4.0 each.

Starting: 4.0 grains
Max: 4.0 grains

Unfortunately, the .46 hole in the disk gives 4.2 grains of powder, while the .43 hole gives 3.9 grains of powder. I can't get anywhere between those two figures.

.46 hole: 4.2 grains
.43 hole: 3.9 grains

My question......is it better to go over the recommended amount or below? Will there be any risks involved with either amount? Is accuracy affected with either load size?

I'm shooting a Springfield 1911.

Thanks again

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May 21, 2010, 08:35 PM
The Lee manual is good for referencing, but you should seek more information to make an informed decision.

www.alliantpowder.com distributes Bullseye, and gives a maximum of 4.6gr of Bullseye with a 200gr Speer LSWC, and recommends a 10% reduction to start. That would be near 4.2gr for a starting load.

To answer your question, it's prudent to use the lower charge in most circumstances, but you do need to cross reference loads from different reliable sources.


May 21, 2010, 10:17 PM
As far as getting the right load, you can try the charge bar for the Lee Powder measure, it is supposed to allow you to make fine adjustments to the charge. I have one but it is still in the box so I can't really comment on if it works or not as my double disk set is throwing properly for me.

May 21, 2010, 10:27 PM
Go light/3.9, it'll shoot.

Lee offers a micrometer adj. powder 'disc'. I didn't find it reliable/consistent.

FWIW: The discs are about $5 each. I've successfully modified a hole to throw what I needed.

Pick a drill bit that's just slightly larger than the hole. Turn the disc 'upside down' and using a drill press slightly enlarge "the bottom" of the hole about 1/4" deep. Reinstall the disc and measure the powder drop. It will be slightly higher than it was. if it's 3.95grs then drill slightly more from the bottom and retry it. If it's close, use some 1000grit sand paper and 'polish' the inside of the drilled area. This might raise the drop just another skosh.

This has worked perfectly for me twice. I paint a new number on the face of the disc (in this case hole #44) so I'll know what it throws. The chart will still work. I've reloaded thousands of rounds using my modified holes and they are completely consistent and accurate.

It's important that you only drill from the bottom side of the disc so there won't be a 'ledge' to catch powder.

Jim Watson
May 21, 2010, 11:15 PM
You really need a scale so you know what the holes are actually delivering instead of what it says on the chart. They seldom match. Usually lighter, but you need to KNOW.

May 22, 2010, 12:33 AM
Sorry if I didn't make myself clear enough......I am using a scale to measure the drops.

Both drops are pretty darn consistent every time: 3.9 and 4.2

Thanks for the advice 1SOW, I think I might try to drill at the bottom of the disk. All I really care is that it fires consistently and reliably every time. Right now, I'm not doing anything with my reloads except punching paper and blowing up gallon jugs of water.

May 22, 2010, 04:37 AM
To be honest, I don't think drilling out a perfectly good disk is warranted for 0.1 grain difference. I am happy if my match powder charges are within 0.1 grain in variance.

Have you tried "sleeving" a larger Auto Disk hole to see if you can get a custom powder charge?

Also, as mentioned, you can try the adjustable charge bar.

Dave B
May 22, 2010, 05:34 PM
You won't notice .1gr difference at all. Go 3.9

Mad Chemist
May 22, 2010, 06:26 PM
I'd use the Alliant data after all they manufacture the powder.

Lee load data, especially the stuff that comes with their dies, is often weird and inconsistent. The data from the dies isn't cross-referenced to a published manual.

I like Lee equipment but I'm not a big fan of their data.

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