Is there any chance anybody out there has loaded the GS HV bullets in the 338-378 Wby? I'm shooting a stock Weatherby rifle (i.e. SAAMI freebore).

Ken....

Wow!

I'm glad somebody has had some experience with this. It appears I'll just have to guess.

Ken....

Ask Gerard ...

Hi Heat,
I have the case capacity listed as 137 grains of water for a 338-378. What is your barrel length and which bullet do you have? If you could measure a case for capacity in water, that would be usefull to get closer. I will crunch the numbers and sort a start load for you.

quote:

Originally posted by Gerard:
Hi Heat,
I have the case capacity listed as 137 grains of water for a 338-378. What is your barrel length and which bullet do you have? If you could measure a case for capacity in water, that would be usefull to get closer. I will crunch the numbers and sort a start load for you.

I'll get the capacity when I get home today, hopefully my memory will work. I have read that the case capacity is 137 grains but I'll verify that with an actual weighing.

The rest of the details would be: barrel length is 26 inches (stock Wby Accumark with brake) 1 in 10 twist. The bullet would be the 225 grain HV (338225HV055). By the way, so far the rifle has liked any of the Barnes X variants with IMR-7828. What is your take on moly vs. non-coated?

Ken....

My measurement came out to 134.4 grains of H2O. The case was a twice fired Norma/Weatherby case that hasn't been resized since last firing but was trimmed to length before the last firing. Hopefully you can find a starting point from here. Thanks Gerard.

Ken....

Heat,
Here are some suggestions that should be usefull. Please visit our Load Data page for an easy procedure to load development. Also, on the pages containing the load tables, there are explanations of the column headings which will help, particularly with the conversion from 24" barrel to your 26" barrel and other data.

338-378 Wea Mag - 228225HV055 - 1:10"
Powder ------ Start gr - MAX FPS - FPS/Inch - COL/mm - % Fill - Burn --- M/PSI
ADI AR 2214 - 113 ------ 3300 ---- 37 ----------- 96 ------- 103 ---- 100 --- 17101
R/shot Magnum 115 ------ 3325 ---- 38 ----------- 96 ------- 102 ---- 100 --- 17713
Norma MRP --- 107 ------ 3300 ---- 37 ----------- 96 ------- 97 ---- 100 --- 17303
IMR 7828 ---- 106 ------ 3300 ---- 38 ----------- 96 ------- 103 ---- 100 --- 17386
S 385 ------- 102 ------ 3225 ---- 35 ----------- 96 -------- 96 ---- 100 --- 15603
Viht N560 --- 107 ------ 3325 ---- 39 ----------- 96 -------- 99 ---- 99 ---- 17956
Win WXR ----- 106 ------ 3300 ---- 37 ----------- 96 ------- 102 ---- 100 --- 17187

If I can help with anything else, contact me on gerard@wol.co.za

Thanks Gerard, it looks like time to get started with these.

Ken....