Working up loads....

[NSP64]

when working up loads, how much change do you make each time? I am working a small case (30gr max) and was working up .5gr at a time. I was wondering if I missed the 'magic' amount. Should I go up in smaller incriments?[smilie=b:

[462]

Half-a-grain should do it till you close to your desired accuracy or velocity, then you can go to tenth-of-a-grain. Just my two-cents.

[geargnasher]

Depends. Powder type and burn rate, boolit weight, case design and capacity all make big differences.

I study as many sources as I can for the combination I'm wanting to try to try to get an idea if the pressures build suddenly near max or are more linear. If linear and I want to approach max then I work up .2 grains for the last grain.

If I'm working up an accuracy load (say, HS6 in a .357 Mag, starting at .38 pressures) I may work up from 4.5 to 10 grains 1 to .5 grains at a time.

If I'm working up .30-'06 loads I would go 2 or 3 sessions, one to "rough out" what my gun likes with a couple of different powders and boolits, then take the best and fine tune in .2 grain increments.

I think everyone has their own algorithm for working up loads based on their experience, the more of which you have the less trial and error you have to do.

FWIW.

Gear

[felix]

"when working up loads, how much change do you make each time? I am working a small case (30gr max) and was working up .5gr at a time. I was wondering if I missed the 'magic' amount. Should I go up in smaller increments"?

The answer is yes, but only for finding the mid-point of the horizontal portion of the velocity curve. If there is no horizontal portion, select a different powder close to the same speed. You DESIRE 0.2 grain Plus and Minus, about the selected MEAN powder dump. This should take care of any reasonable condition changes in the field. ... felix

[Blammer]

.5 grain is a good one, I don't think you'll miss the accuracy window that way.

[dale2242]

I`m with DJ. With a 30 gr. capacity .5 gr increments is what is what I use.---dale

[fredj338]

It's very powder/case specific/ There is no magic number like 1/2gr. If you are working w/ fast powders in large cases, ie W231 in 44mag, then1/2gr is way to much spread. Even med. burners like Unique a 1/2gr may be too much. For pistols I break my charge wts. down by burn rate. For powders faster than Unique, 0.1gr uncrements. Powders from Unique to Longshot, 0.2gr increments & slow powders like 2400, H110, AA#9, then 1/2gr. FOr all my rifle stuff, they are all above 50gr volumn, then I use 1/2gr -1gr increments.

[geargnasher]

"when working up loads, how much change do you make each time? I am working a small case (30gr max) and was working up .5gr at a time. I was wondering if I missed the 'magic' amount. Should I go up in smaller increments"?

The answer is yes, but only for finding the mid-point of the horizontal portion of the velocity curve. If there is no horizontal portion, select a different powder close to the same speed. You DESIRE 0.2 grain Plus and Minus, about the selected MEAN powder dump. This should take care of any reasonable condition changes in the field. ... felix

:holysheep That's the Ph,D answer to a "Reloading 204" question. I used to do basically that with my benchrest loads, back when I had unlimited access to a friend's chrony and no life. I also had a formula for standard deviation memorized. Took me forever to realize that the right powder can have an almost flat portion to the curve, loading to the center of that and correcting the optics tends to give the best consistency (most important to me in bullseye competition) through a broad range of temperatures and shooting cadences (ie barrel temp).

But back on topic, I worked 6mm PPC up .5 grains with several powders to ballpark the velocity curve, then refined around the peak (if there was one) in .1 grain increments. Amazing how much difference that can make at 500 meters. But for most normal stuff you don't have to be that precise.

Gear

[HORNET]

I've seen recommendations in a couple of my reference books to go in 2% steps. For a charge of around 10.0 grains, this would be 0.2 grains. For a 30 grain charge, it would be 0.6 grains. I know one guy that claims that he could tell the difference with 0.1 gr steps in his .22 Hornet. If you try .5 gr steps in something like a .25 ACP, you run out of steps real quick...