I asked a very similar question when I first joined this site. The answer I was given was that .338WM just will not push heavy bullets fast enough to be useful. The problem is not energy, it is the fact that the bullet is dropping so much as to make it very difficult to hit your target at long range.
The general consensus was that the .338WM is not really a long range cartridge. One of the very experienced long range shooters/hunters who frequent LRH.com, LongTimeLongRanger, maintains that the .338WM is at its best as a light rifle shooting either 185g Barnes TTSX's or 225g Cutting Edge bullets. He states that the 185 TTSX's allow for much easier hits out to 700 yards or so and the 225 CE's out to closer to 1000.
If neither one of those options does it for you, then stepping up to .338RUM would probably be the way to go.
My 2 cents are, well you have it so why not. But what are the numbers withe the 250g, may be a better option?
I agree! For now, I load 225g on mine.
I read an article last year but cannot seem to find it, but the gist of it is "the .338 Win Mag does not have enough powder capacity to generate enough velocity to take advantage of the 300g Berger's BC".
I say go for it and lead the way!
I voted for my "FREEDOM", "GUNS", and "MONEY" - keep the change - UNK.
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I am interested in hearing how the 250gr Bergers work out with the 338wm.. A while back i tried to get some feed back on how well this comb. would work with little to no response. I think with the 250gr and 300gr berger pills the only way to use them is to single feed. i don't believe they fit into the box mag.... if someone has the Berger loading bible if they could post the data for the 338 wm with the 250gr pills using irm 4350 ill see if i can get sometime this week to work with it.
+1 on the 300gr being a little heavy for the 338 wm.
My dear boy if 5 miles away they don't sit up in their beds and ask what the HELL was that, the gun is not big enough!
I built a 14 lb rifle with a LA to shoot the 338 RCM long throated for the 300 gr ,match tactical hybrids. I chose a 1 in 9 1/2 twist 30" barrel. Bullets are lumbering along at a bit above 2500 fps using RL-17.
Have put hundreds of rounds through this rifle. It is very accurate with moderate recoil. The barrel should last a long time as it only uses 56 gr of powder.
Shot a coues wt last fall with it at around 275 yd. Bullet didn't open much and deer died a bit slower than it might have with a lighter hunting bullet. No bloodshot meat with a caliber entrance hole and a 1/2" exit hole.
I'd say it might be fun to give it a try with your 338 win mag.