Best Interval of powder charges when finding optimum load

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  • Last Post 21 February 2025
John Alexander posted this 14 February 2025

When trying to find the best load of a given powder for your pet rifle, what is a reasonable interval between groups for the power weights under consideration?

Since a 0.5 grain interval for loads around 5 grains is 10% and the same 0.5 grain interval for a load around 30 grains is 1.7%, let's keep the discussion in percentage of the load instead of in grains. Discussing the intervals in grains only makes sense if the load is also mentioned and it would be harder to compare different opinions.

Thanks in advance for your replies.

John

 

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Premod70 posted this 14 February 2025

Starting out with the fast burning powders in 0.5 grain intervals works for me, 1.0 grain for the slow stuff. Once I hit the best load I will usually go a 0.1 grain plus or minus to see if there is any improvement. If there is some gain I may continue another 0.1 grain or some in the positive direction in hopes of a even better result.

Dale Flinchum

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RicinYakima posted this 14 February 2025

With pistol powder I usually start at 5%, one twentieth of the minimum recommended. Anything slower than A2400, I go with 10% over minimum. 

Remember, I am looking for target loads, 1400 to 1600 f/s. After I shoot a couple of ten shot groups with that big of splits, I go 1/10 grains. Sorry John, don't do percentages fine tuning loads. 

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Bud Hyett posted this 14 February 2025

The powder measure is giving +/-.1 grain variance at best in normal operation. This is a .3 grain range in best operation.

Given this condition, I go with a .5 grain differential for most loads less than 40 grains. With loads above 40 grains, jacketed usually, I go in 2 grain jumps starting with a ten-percent reduction from maximum.

Farm boy from Illinois, living in the magical Pacific Northwest

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Fiddler posted this 14 February 2025

I've kind of settled on .3 for hand gun and .5 or 1gr (depending on powder) for rifle. Never looked %'s.

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Shuz posted this 14 February 2025

I'd say 5% is a Happy place to start.

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John Carlson posted this 15 February 2025

Most of the 30-06 loads I use are somewhere around 20 grains.  I generally have an idea where I'll end up so load in 2% increments above and below for a total of 10 loads.  Results from that session will guide my next outing.

John Carlson. CBA Director of Military Competition.

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OU812 posted this 15 February 2025

I've always use reloading book intervals since every powder is different. Why figure percentages since powders are so different. Without the reloading manual I usually use "one grain" increments, chronograph and best grouping.

 

I've  used one grain increments 4,5,6,7 grains of Titegroup. My favorite with 72 grain 223 bullet is 6 grain. WARNING do not doubled charge.

 

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RicinYakima posted this 15 February 2025

Tired of reading this "double Charging" stuff. That is a process error because you are doing it wrong. Pick up the case, put the powder in it, see if it is twice a large as the last one, seat the bullet. Done. 

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John Alexander posted this 21 February 2025

This topic has run out of steam.  Several interesting posts.  Thanks for your responses.

John

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