Best powder for 250gr in 338 WM? Anyones pet loads?

Charlie38

Charlie38

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Northwest (Prince Rupert), BC
Dues to the Canadian shortage I have 2 lbs of IMR 4350, 2lbs IMR 4831, 4 lbs R19, 2.5 lbs R22, 2 lbs IMR 7828, 1.5 lbs H4831.
What has been your most accurate powder in the 338WM with 250 gr bullets, I have 100 250gr Accubonds and 80 Hornady 250 RP-SP Interlocks.
2700 fps is fine.
I want to work up a load but still have enough for hunting season in case I can't find anymore. Moose and elk on the agenda this season.
Thanks in advance :)
 
I have played around with IMR 4350 and 4831, and also RL 19 with my 338 using 250 gr Partitions. RL 19 performed the best in my own rifle.
 
Length of barrel will affect performance. For <26" barrels I'd bet on the H or I 4350 for good accuracy. R19 by all accounts should work fine. I would use hodgdon site for load data. I would burn up the interlocs for load testing then test around the accuracy nodes with the accubonds. 0.5gr load spacings should work fine. 3 test shots at each interval within 2gr from max will leave you with a lot of bullets/powder for hunting down the road. Your shoulder will also appreciate the minimum shot approach...hold er tight.

Look to slower powders (H4831, R22) if you have a 26" barrel. 250s in the 338WM are like bread with butter.. they just go together. Good luck with your quest...your barrel will let you know.
 
With a Model 700 Classic and a 24" barrel, I worked up to 72 grains of IMR4831 using the Nosler Partition 250 grain.
Chrony read 2750 fps which was over book velocity.
Accuracy was better with Federal MR primers versus CCI 250 primers.
It was not to be used in warmer weather!!! Three shot groups were under one MOA.
 
67.5 grains of IMR4350 is a max load in my Tikka M65 Standard, when using a 250 grain Hornady Spire Point bullet......I use CCI-250 primers and R-P brass......I have used the same charge of IMR4350 with the Accubond 225 grain bullet and it groups right at one inch....my most accurate load to date for this rifle.....I get 2,715 with the 225 grain bullet and 2,650 with the heavier bullet....

IMR4350 bulks up just about right for the 338 Win Mag.......as mentioned by Ken Waters in his Pet Loads write up....
 
I ended up trying 3 different loads... all with 250gr Accubonds.
1. 71.5gr H4831 (Nosler book max) accuracy right around 1" 3shots @100yds but MV of only 2585fps.
2. 75gr R22 accuracy 1 1/8" 3 shots @ 100yds MV 2707fps
3. 73gr R19 accuracy just under 1" 3 shots @ 100yds MV 2724fps - I also got a 1 1/4" 3 shot group @ 200yds with this load...its the winner.
 
Make sure to check that rl19 load in the cold, if you hunt when it's cold out that is. In my own experiments I lost over 100fps shooting a rl19 load in 338 wm between +25 and -20. That might make your groups open up as well. If you are aware of this, disregard my post but often people do their load development in the summer time and then don't chrono in the winter and then can't figure out whey they miss an animal and have no time to work up another load in the cold weather when its hunting season. I have had equally bad results with rl22 losing lots of speed in cold temps as well. Just a heads up.
 
kman300 said:
Make sure to check that rl19 load in the cold, if you hunt when it's cold out that is. In my own experiments I lost over 100fps shooting a rl19 load in 338 wm between +25 and -20. That might make your groups open up as well. If you are aware of this, disregard my post but often people do their load development in the summer time and then don't chrono in the winter and then can't figure out whey they miss an animal and have no time to work up another load in the cold weather when its hunting season. I have had equally bad results with rl22 losing lots of speed in cold temps as well. Just a heads up.
Click to expand...
Will do thanks :) I should be good for my moose draw, its mid October and it might be -4 at the worst then. I shoot during hunting season to check my zero all the time anyways, I just like shooting.
 
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My group with R19 250gr Accubond 2724fps 100yds
 
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