If you’re using Lapua brass, because it’s so much thicker and the volume is so much less, all the published numbers use Winchester or Remington or some other case that can hold a lot more powder, more volume. Is there a thing you do to adjust that percentage-wise because of the change in case size?
For example, for Varget powder for 308, if the start is 42 grains and the max is 45 grains, do you subtract, let’s say, 2 grains off the start and the max and go from that? Is there something you do that normally accounts for this? Obviously, it brings it down into a safer range, but is there a better way of thinking of it? Thanks.
I’d recommend just starting at the minimum and working your way up until you find something that works or you start to see signs of pressure. I only use lapua brass for my TR rifle in .308 and using AR2208 (Varget) with a 155.5 Berger my standard load is 46.3 gr with no sign of pressure
I use GRT to look for grain weight and pressure. I then go below max pressure for load.
For example, my AGD brass has a case volume of 79.84 which is less than the federal brass I started with. So I had to reduce the powder from 66gr to 65.5 to keep the pressure the same, relatively.
I’ll either use GRT to find the max load and go slightly .5-1 grain lower or go that same amount below book max and send it. I use this method regardless of whatever brass I’m using.
I’m using a new bullet in 22 CM with no load data currently and that’s my only exception where I will do something different. I used GRT and will start lower and go up in .5 increments watching for pressure. My max load is right at max pressure but where it’s new and untested, I’m more cautious.
I.e if the theoretical max load with the new bullet was 39 grains of H4350 . I might do 37.5, 38, 38.5, and 39g loaded ammo to make sure I don’t see pressure early. Assuming no issues, would likely end up around 38-38.5 grains.
Some people love load development. I do not. I just want a simple and easy load that works.
Thanks ., there is a definite early spot in ladders where there is to much volume in the case for sure. i’m shifting down the full rage by 2gr. running a 16 step ladder up to the new max and seeing whats the results from there. It iuts sounds off please jump in.