OK, I tryed some 225 gr barnes in my 338 winchester and was able to get awsome accuracy with 72.0 gr of RL19. I thought I'd try the 250 grainers, but am not getting nearly similar accuracy with 70.5, 71.0, 71.5, or 72.0 grains of RL19. With the 225 grainers I was getting around 1/2" groups at 200, but the 250 grainers are all doing 1 1/2" groups at 100. I didn't trim my cases, or weigh them this time because it was the last time I was going to use them.
1) do you think I should give the 250 grainers another chance, while applying the same case preping procedures as I did with the 225 grainers, or go back to the 225 TSX load? would the 225 gr be enough for everything the 338 is meant for?
2) When I got the awsome groups, it was -11 degrees and gusty out. do you think the spring warmth would change the accuracy of that load?

If you have any accurate RL19 loads for the Barnes 250 gr TSX in the 338 win, go ahead and share.

I've had good accuracy with 250 gr sierra game kings too.

I too tried the 250s in my first 338 WM and couldn't get em to shoot anywhere near as accurately as the 225 grainers. I just bought another 338 WM and it shoots great groups wth the 225 grain pills so I'm not gonna pursue the 250s.

Is the 225 grain enough bullet for the 338 WM? Absolutely, since 1997 I have hunted exclusively with the 225 grain original X-bullet. I still have about 50 of em left and then I'll switch over to the Tipped TSX. I have taken Sitka Blacktails, Caribou, Goat, Moose, and stuck bullets through 3 brown bears and one grizz. In every case, they did the job. Excellent expansion and penetration.

What will you give up by shooting 225 vs 250 grain bullets? I asked one of the guys at Barnes the same question back in the late 90s. His response was the 250 grain X-bullet will give you about 2 inches more penetration and 100 ft lbs more energy than the 225 X. I'm sold on the 225 grain X-bullets and if they shoot well in your rifle, IMHO you're good to go for anything in North America.

If you want to fairly evaluate one bullet weight versus another, you should be as consitent as possible with case prep, primer seating depth, powder weight, and probably most importantly, bullet seating depth. Bullet seating variation can make a big difference in group size.

With regards to weather and your group size, I haven't found any correlation between group size and weather aside from obvious long range shooting. Out to 100 yards, I don't think typical weather variations make a big difference.

I tried the 250 gr TSX's with RL22 and IMR7828 and did not get very good accuracy. But the thing I remember most was the amount of compression with that very long bullet. I was using 74 to 75 gr powder. The Nosler manual lists those loads as compressed and over 100% load density. Perhaps with RL19 and a couple of grains less then it might be better.

I also tried the 250 gr Sierra Game Kings but still no accuracy. I'll stick with the 225 and 210 grain bullets until I rebarrel to a 338RUM.

thanks for the great responses.
I'm getting more of the 225 gr TSX. I was thinking of going with the tipped version because they only cost $3 more per 50, but I thought why if the TSX already shoots as accurately as I could possible shoot. If anyone trys those tipped 225 grainers, let me know how you like them. I've heard the tip will help ensure expantion or something to that degree.
Oh, for the weather factor, I know wind will effect accuracy, but I was wondering if a jump from -11 to 75 degrees would cause enough of a velocity change to effect accuracy greatly. I'm sure the only way to find out is by trying it.
Now I've got 250 gr Sierra GameKings shooting 1" at 200 yards
225 gr TSX shooting 1/2" at 200 yards
and I'm going to try 225 gr Nosler Accubonds for the hell of it.

Oh, yeah, winchester brass is out of stock at midway, So I'm trying the Nosler (weight seperated) brass. If the brass is good and all weighs the same, it could be worth the extra money for the time I save not weighing it.

With regards to temperature affecting velocity, I think it does. I've been watchin for this lately myself as I'm working up a good load for my newest 338 WM. I Googled the topic and found Sierra did a test with three calibers and found roughly an increase or decrease in velocity equal to 1 fps per 1 degree of temperature. If that is correct, your loads from -11 to 75 should show a similar change in velocity. I still haven't seen that big a difference in velocity over the last three weeks and I don't think it significantly changed my point of impact. Still, a case could be made for sighting in during temps similar to what you expect to encounter while hunting. I essentially do this anyway as I go to the range to shoot to verify my zero just before going hunting. I personally don't think it will mean the difference between a hit and a miss at reasonable shooting distances but it may change POI slightly.