I was using a Hornady Bench Mount Powder Drop to load 50 9mm cases this evening with Unique powder. I had the Pistol Rotor and Micrometer. I was looking to charge each case with 4.7GR of powder. After each powder drop to my digital scale pan, I would weigh it. Majority of my charges were fluctuating btwn 4.7 - 4.8 with the occational 4.9 and 4.6. The maximum charge is suppose to be 5.0GR. My question is, how picky should I be on this. If the drop a charge and it weighs 4.8 or 4.9, should I through the powder back in the Powder drop and do it over? Or if I am looking to get 4.7GR, should I just use the drops that measure 4.6, 4.8 and 4.9?

You may see a little larger group but not much when you do the theory work with velocity. I'd probably go with it.

Usually you throw the powder charges into the shell in your loading block then weigh a sample of them say 1 in 5 or 1 in 10. Throwing powder to get consistant charges requires a rythym to get even powder weights. If you let the powder settle in to the measure it can get a heavy charge, to fast gets a short charge. Something else to keep in mind for powder charges is that large measures for rifles have problems accurately measuring small charges. For .45 ACP I have the dispenser set up for 5.4 grains, 5.2, 5.6 no worries when I pull one to measure. When I hand threw before the progressive I was a little pickier .3 to .5.

It is ten years plus since I loaded any pistol cartridges. But FWIW I would not use a powder thrower like an RCBS Uniflow (or similar) with Unique. Or Herco. Or Red, Green or Blue Dot.

Why? I don't think it meters that well because of the powder shape. HP38 or Bullseye no problem or the European powders like Vihtavouri N320 (my "go to" 38 Special powder) or the Italian (I think) GM3 powder yes.

But any of the Unique type disc powders? No.

If it's me and I'm continuously getting +/- .1 grains of drop and am double checking each one.....I'm loading ammo using all of them...

The variance will never be noticed.

I use a Belding&Mull powder measure and it seems to stay right on. I read some measures wont meter some powders, but the old Belding & Mull seems to handle them all.

It should not make a difference.
If they were going over 5.0 I would look at some other way to get it done.

With pistol cartridges, if I'm bumping up against the max, I'm pretty careful about a .1 grain especially if it's that much more. In that case with the max loads I will weigh each 5th one and adjust the thrower back to the correct amount.

If the loading is mid range of the recommended loadings for a pistol I can go with .2 grains and know that I will account for more dispersions in the group than the loads. In that case I will measure every 10th one and adjust the thrower to bring it back to the target load.

For small caliber rifle I will measure every 10th one, adjust the thrower and try to stay within a .1 grain difference.

With large caliber max loaded rifle loads I will throw and then trickle the powder to come up to the exact measurement before seating the bullet. This take a lot longer but I usually find that I'm not reloading a large volume of cases with the larger rifle rounds.

I don't know how long you have been reloading but when using a powder measure, the consistancy of your technique has a great deal to do with how consistant your loads are. FWIW, I lift the lever and give a double tap (to settle the powder), and then I lower the handle and again give it a double tap (to clear all powder). I am also rather abrupt with my up and down movements.
In truth however, most, if not all, of the measures, manual and electronic, are only guarenteed to 2/10ths of a grain.
Why not take a deliberate mix of your charge weights and see how it affects your accuracy.

I set my powder throw to drop 5.5 grains then trickle feed on the digital scale up to 5.7. Sometimes it drops as high as 5.9 in which case I dump it back into the powder dispenser and drop a new one.

Even when building IPSC competition ammo at the old major power factors, ball powders work well enough though good powder measures to work at very near max pressures.

Fortunately, the power factor requirement has been reduced from 175 to 165 which gives some head room and is much easier on equipment.

I do weigh every charge for match and hunting ammo for rifles.

quote:

Fortunately, the power factor requirement has been reduced from 175 to 165 which gives some head room and is much easier on equipment.

Really? When was this? No longer shooting any IPSC (or handguns) here in UK all this passes me by!

quote:

Originally posted by PaseMkr:
I was using a Hornady Bench Mount Powder Drop to load 50 9mm cases this evening with Unique powder. I had the Pistol Rotor and Micrometer. I was looking to charge each case with 4.7GR of powder. After each powder drop to my digital scale pan, I would weigh it. Majority of my charges were fluctuating btwn 4.7 - 4.8 with the occational 4.9 and 4.6. The maximum charge is suppose to be 5.0GR. My question is, how picky should I be on this. If the drop a charge and it weighs 4.8 or 4.9, should I through the powder back in the Powder drop and do it over? Or if I am looking to get 4.7GR, should I just use the drops that measure 4.6, 4.8 and 4.9?

Your problem is your digital scale, which will give .1 grain variations in readings due to a plethora of causes that electronic scales are prone to. Borrow a good balance beam scale and you'll find that your charges are much more consistent than you believe. I've never seen a pistol powder that would vary as much as .1 grain in charges when dispensed from a brand-name measure in such small quantities.

You talking about 1/10 of a grain of unique about 5-6 flakes of powder and 10fps in a 9mm
I don't think I would worry over it I doubt you can hold your gun that steady to make a diff.

Throw that damn elec scale away and buy a RCBS 1010.