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Old December 27, 2008, 10:33 AM   #2
Join Date: March 4, 2005
Location: Ohio
Posts: 16,351
Welcome to the forum.

Very few people in the U.S. try to reload 25 ACP, so you won't find much information. Part of the reason is the small charges are difficult to weigh and dispense accurately. The small cases are very sensitive to powder charge level so it is easy to exceed maximum pressure with normal weighing error.

Most loading scales resolve either 0.1 grains or 0.01 grams. That is not enough resolution to be consistent in such a the small case. With charges on the order of one grain, that represents 10% difference in powder charge. You will need a lab scale resolving 0.02 grains or one resolving 0.001 grams to control such a small charge accurately. Otherwise, again, you need to settle for a mild charge so that weighing error doesn't accidentally cause excess pressure.

The only published load data I have for the .25 ACP is in the old NRA Handloading book. It calls for: 1.0 grains (0.065 grams) to
1.3 grains (0.084 grams) of HP38 with the 50 grain round nose Hornady FMJ bullet.

The QuickLOAD internal ballistics software estimates with the S&B bullet that 1.0 grain (0.065 gram) is a mild load of HP38 and that 1.4 grains (0.091 grams) is too hot in that small case with some lots of powder, but OK with others. This agrees well with the published data for the Hornady bullet, so the two bullets appear to be interchangeable. Since you probably have a conventional powder scale, I would start with 1.0 grains and work up near to 1.2 grains or 0.08 grams. I would probably not exceed 1.2 grains or 0.08 grams unless I had a higher resolution scale.

For speed, I would consider making a small dispenser and measure powder by volume rather than by weight. In that small size it may be more consistent. You can solder a wire into the extractor groove of a fired .25 ACP case to act as a handle. clean the inside of the case well and fill it with solder until there is just enough room for the small powder charge. Use a file to further reduce the volume if needed, or a drill to make it bigger. Use this as a dipper and level the charge with a plastic card. You can put 10 such charges on a scale to weigh, then see what the average weight is? Do that several times and the groups of ten should have an error that is ten times smaller than your individual dispensing error, so you can get some idea of what that error is, too?

Good luck with it.
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Last edited by Unclenick; December 27, 2008 at 10:55 AM.
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