The Firing Line Forums - View Single Post - How do you set up your powder dispenser for a particular charge?

Edward429451 · July 7, 2012, 12:15 AM

Whenever I buy a new can or jug of powder I sit down and weigh ten charges and record each charge on a slip of paper, and then apply all the chrony formulas to it. I get the avg, high & low extreme spread, and average deviation from average each throw. Then I tape this to the can of powder for reference when I use the powder.

To set up my measure (RCBS Uniflow), I first zero my scale (RCBS 5-0-5), fill the hopper at least 3/4 full and throw a couple charges to settle the measure and see where I'm at with this particular powder. When I cycle the powder cylinder, I give a definitive tap at the top and bottom (and watch the powder flow through the drop tube thingie), Only one tap top and bottom, with an effort to use the same amount of force for consistency.

I see where I'm at and dial the measure adjustment up or down towards my target weight. After each adjustment of the stem I throw a couple throws to settle it and then weigh the next one. If it is a new load or destined to be something better than standard range ammo, I will take the time to fiddle it to exact as possible considering the variance you will get with different flakes of powder. I refer to the note on the powder and assure that I am getting no more variance than I was getting before.

For example, I have a 180 gr WC load with 5.5 grains of Trailboss. Looking at my note on the bottle of Trailboss, I see that it flows thru my Uniflow with .03 average deviation from average, and with a .2 extreme spread (+- .1), so I try to dial in my measure to 5.5 since I'm not max. That's exact enough for me. If I was riding max then I would target 5.4 (arbitrary) so the most I could get was the 5.5 (or whatever max load.) I like longer barreled pistols so it is very easy for me to achieve high velocity with less than max loads, often starting loads.

July 7, 2012, 12:15 AM	#4
Edward429451 Junior member Join Date: November 12, 2000 Location: Colorado Springs, Colorado Posts: 9,494	Whenever I buy a new can or jug of powder I sit down and weigh ten charges and record each charge on a slip of paper, and then apply all the chrony formulas to it. I get the avg, high & low extreme spread, and average deviation from average each throw. Then I tape this to the can of powder for reference when I use the powder. To set up my measure (RCBS Uniflow), I first zero my scale (RCBS 5-0-5), fill the hopper at least 3/4 full and throw a couple charges to settle the measure and see where I'm at with this particular powder. When I cycle the powder cylinder, I give a definitive tap at the top and bottom (and watch the powder flow through the drop tube thingie), Only one tap top and bottom, with an effort to use the same amount of force for consistency. I see where I'm at and dial the measure adjustment up or down towards my target weight. After each adjustment of the stem I throw a couple throws to settle it and then weigh the next one. If it is a new load or destined to be something better than standard range ammo, I will take the time to fiddle it to exact as possible considering the variance you will get with different flakes of powder. I refer to the note on the powder and assure that I am getting no more variance than I was getting before. For example, I have a 180 gr WC load with 5.5 grains of Trailboss. Looking at my note on the bottle of Trailboss, I see that it flows thru my Uniflow with .03 average deviation from average, and with a .2 extreme spread (+- .1), so I try to dial in my measure to 5.5 since I'm not max. That's exact enough for me. If I was riding max then I would target 5.4 (arbitrary) so the most I could get was the 5.5 (or whatever max load.) I like longer barreled pistols so it is very easy for me to achieve high velocity with less than max loads, often starting loads.