Tweeking a load for the best accuracy

[hunter284]

When starting this process, such as cartridge over all length , how many thousandths change in depth will result in a change in group size?

 

[BallisticsGuy]

I like to test .010 jump, .040 jump, .080 jump and .120 jump. If it shows a definite trend toward liking small jumps I MAYBE will try them touching/jammed. With those, admittedly wide, spacings you'll see a trend for sure. After that, might be helpful to measure bullet base to ogive and get the extreme spread from a good size handful, then take twice the spread and call that your increment. FWIW, I've not had to go finer than the increments listed above to get a one-hole load since I started using this system.

We can thank BoxToBench Precision for the above. In fact, you might want to check them out. They make a load development target just for this with those values on the target, that's where I got them. I used to go with a more rectally derived guess and much finer increments. The B2B way I burn a lot fewer rounds developing loads.

 

[Clay Target Guy]

I am by no means a expert but this is what I do.
I start with the bullet touching the lands (or as close as I can) I try a few different powder types and changes. If I find a charge that gives me the velocity, SD, ES, etc. I am looking for, I load up 50 rounds and head to the range. I carry my seating die and a small press. I shoot a group with the bullet touching, I then seat the bullet .010 deeper and try another group. I repeat at .010 until I get the tightest group and then go to .005 of either side of the group.

 

[hunter284]

I like to test .010 jump, .040 jump, .080 jump and .120 jump. If it shows a definite trend toward liking small jumps I MAYBE will try them touching/jammed. With those, admittedly wide, spacings you'll see a trend for sure. After that, might be helpful to measure bullet base to ogive and get the extreme spread from a good size handful, then take twice the spread and call that your increment. FWIW, I've not had to go finer than the increments listed above to get a one-hole load since I started using this system.

We can thank BoxToBench Precision for the above. In fact, you might want to check them out. They make a load development target just for this with those values on the target, that's where I got them. I used to go with a more rectally derived guess and much finer increments. The B2B way I burn a lot fewer rounds developing loads.

Thanks so much for this info. I will try your suggestions with a new 308 I am having built. Rich

 

[hunter284]

I am by no means a expert but this is what I do.
I start with the bullet touching the lands (or as close as I can) I try a few different powder types and changes. If I find a charge that gives me the velocity, SD, ES, etc. I am looking for, I load up 50 rounds and head to the range. I carry my seating due and a small press. I shoot a group with the bullet touching, I then seat the bullet .010 deeper and try another group. I repeat at .010 until I get the tightest group and then go to .005 of either side of the group.

 

[hunter284]

Thanks for your input. This will get me started with a 308 I am having built. It's just a hunting gun, but I always strive to get the most accurate load to use and if I miss, it's my fault and not the load.

 

[Canhunter35]

Saami reamer on the 308?
If you're using a short action magazine you won't get near the lands on saami 308 chamber.

 

[hunter284]

Saami reamer on the 308?
If you're using a short action magazine you won't get near the lands on saami 308 chamber.

Thanks for answering my request. Actually, I am having a Ruger Hawkeye 243 rebarreled to 308. I am not sure what reamer they will be using. I will have to find out.

 

[COBrad]

Put a Wyatt box magazine in the rifle if they make one for it.

 

[hunter284]

Put a Wyatt box magazine in the rifle if they make one for it.

Ok thanks, I'll check it out.