truck driver
Well-Known Member
- Joined
- Jun 16, 2012
- Messages
- 168
I've enjoyed your post and I'm impressed that you are taking a case based off the 280 and getting this much performance out of it with .338 cal 250gr bullets.Yes, so far, the ONLY bullets I have seen that can keep up with the Berger in terms of velocity, drift, and drop are monos. Accuracy and terminal performance are still open questions.
The only other .338 bullets that even make sense to me are in the 200 grain range.
I'm not sure why it's such an issue in the .338 diameter, but a LOT of .338 bullets seem to be designed with a long bearing surface, which limits velocity potential. That may not make much difference with the larger cased .338's, but it matters when trying to extract efficiency from cases on the smaller end of things.
I'm shooting a 338Wm and haven't tried anything heavier than 210gr out of it and that is a 210gr Nosler PT with RE17 and getting 3023fps out of a 24" M77 Hawkeye.
I have had trouble like you with the 210gr Swift and can't get much over 2900fps with it do to pressure. I think besides the longer bearing surface the brass jacket material also has something to do with it.
I have torture tested Nosler 35 Whelen seconds brass that I used to form 35W/AI brass pushing a 200gr AB to just under 338Wm velocities along with 225gr PT. I use CFE223 in the 35W/AI with great results.
Some where in your post I missed what the case dimensions are for the 338 Sherman and was wondering if you would repost them. I have a M70 I might like to try building one on.