How neurotic is this?

[rick benjamin]

This won't account for 5 grains of deviation, but it will effect accuracy.
Cartridge cases start as a punched slug of brass.
Hammered and squeezed, formed to what we use.
A friend at work had a super accurate 218 Bee that started to throw fliers.
Turned out he'd bought a new batch of brass for reloading.
I suggested the neck thickness might not be congruent.
He gave me a handfull of his brass to outside neck-turn.
One side of the case was thicker than the other side.
The bullet would not center in the bore until the neck was corrected.

 

[rdt]

The deviations accumulate.

Loading .45acp, I once sampled 100 of each bullets, powder throws, and brass to get a reliable idea of the total ranges of deviation. Then i loaded everything up and weighed the finished rounds. IIRC, (same lot RP once fired) brass had the greatest variation. The important part of all this is if a "heavy" case gets a "light" load it cancels out in the final weighing. So final weighing without uniforming doesnt tell you very much, except tip you off to a double or squib load - *Maybe*

With those .45acp loads I was examining the total possible range of deviation was greater than the the 5.7gr load of Unique. A double load in the lightest case and under the lightest bullet would have a final loaded weight *within* the acceptable range.

 

[Shooter98]

After today, I'd say don't deviate from what ever you've done lol...

 

[speeddemon94]

Yeah, I was just going to come and share! So my loads, in a SIG 226, are killer. Glad I'm neurotic.

 

[Cameron72]

Another something to think about is this. As the hopper empties the the weight of the powder pushing down lessens which may change the charge thrown. Keep the hopper full

Different powders will throw differently. Long cylindrical powders hang up on each other dropping into that space you have dialed into the drop charge measure and they hang up at an inconsistent rate. A nice small round ball powder is more consistent in filling that measure, so less variation from the cylinders. You need to check some powders more than others.
However you run your drop charge measure, run it the same way each time to get more consistent throws.
All this may narrow down variations and that's as neurotic as I get.