Home Forums Hunting & Shooting Ask The Gunwriters Rebarreling an old war horse - lots of pix, improving the cartridge

Load development can be tedious if you are working up min and max loads for 13 bullets using ten or twelve different powders. I should explain.

The ennui for me is with minimum loads, but they are important, so I have to work hard to stay focused. They are established, safe places to start.

Max loads are where 99% of shooters want to start their testing, however. Because of this, my work is concentrated there. In the case of the 30-303, I was using many bullet weights and powders for which no data existed. I had to sneak up on the max loads, and it took time. You don't just say, "I will use x grains of Hybrid V for this bullet." and shoot. I determined theoretical levels first, and built some loads, increasing them in 0.5 grain increments until I got to what I determined was the max. When you're in unknown territory, it's never tedious.



Here's a 1 inch group fired from my 30-303 using 220 gr Hornady RNs and IMR 4064
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I should say here that the majority of reloaders don't give a rat's ass about less than maximum loads. Everyone wants to ride the rocket. That's a shame. For some reason, they want to start at the book max.

Ignoring the obvious for a moment - these max loads may be over pressure for their rifle - one would hope that they wish to combine accuracy with bullet design and hit their rifle's sweet spot. It's hard to convince anyone that squeezing an extra grain into a case may only produce 20 fps more, but push pressure beyond safe levels.

But I understand why most reloaders go for the top end out of the gate.

Look at the min to max powder weights in a reloading manual for a cartridge you shoot. I'll give you an example - a 165 grain bullet for the 308 Winchester. There can be 10 grains or more of difference between their min and max loads. Most reloaders ignore most of the list, starting close to max (some at max ) looking for the magic group.

I determined years ago that the last three grains of powder was where the accuracy was. Let's say that 44 grains of Varget is the maximum powder charge for my 165 grain bullet, I start two grains below that and work up from there. For that reason, my own load data usually lists a three grain swing - 42, 43 and 44 grains. Velocities will be near the safe maximum, and the bullet will work properly. I look to the bullet maker to give me the information I need. I ensure that performance falls within their design envelope.