Max Loads for 6BR with H322?

[RonAKA]

I'm getting prepared for some ladder tests with a couple of Berger bullets; 69 gr. match varmint, High BC FB, and the 80 gr. Match Varmint FB.

Have checked all the sources I can find and got the following for max loads:

69 grain

Hodgdon 70 grain: 30 gr., 3200 fps, 47,000 CUP
Sierra 70-75 grain: 30 gr., 3200 fps
Nosler 70 grain: 30.5 gr., 3354 fps

80 grain

Hodgdon 80 grain: 28 gr., 3005 fps, 47,000 CUP
Sierra 70-75 grain: 27.7 gr., 2900 fps
Nosler 80 grain: 29 gr., 3144 fps

The Sierra data was produced in a 26" 1 in 8" twist barrel, while the Nosler is a 24" 1 in 14" twist. Hodgdon not sure...

This will be in a 26", 1 in 12 twist barrel, CCI BR4 primer, so what do you think for max load. I don't really want a super hot load, so I was thinking of using the Nosler load as the max, and backing off to get 20 loads at 0.1 grain steps. So, 28.5 to 30.5 for the 69, and 27 to 29 grains for the 80.

What do you think? Is that going to cover the potential sweet spots? I plan to measure the case web after each shot and look for 0.0003" over the moderate load as a stop, as well as the other visual pressure signs. Kind of thinking I should not get to that point with these loads??

If it makes any difference I have measured these bullets and got 0.2431" at the pressure ring and 0.2426" at body for the 80 grain. The 69 grain measured 0.2432" at the pressure ring, and the same 0.2426" for the body.

 

[Preacher]

It's a really tough call to tell you where the max is for your particular barrel, once you find it for that barrel it will not be the same for the next one just like it...
You need to find out what each individual barrel will tolerate for your own safety....

 

[RonAKA]

Do you think I have a wide enough range to identify sweet spots?

 

[dmickey]

Why are you so worried about maximum loads? I would think that it would be more important to be able to hit what you are aiming at! In my 6mm BR a load just .5 grain above the starting load gave me one hole accuracy. ;D

 

[RonAKA]

Why are you so worried about maximum loads? I would think that it would be more important to be able to hit what you are aiming at! In my 6mm BR a load just .5 grain above the starting load gave me one hole accuracy. ;D

You are correct, I'm not so much worried about maximum velocity but more about accuracy. I just want to test the window of loads that is likely to give the best accuracy.