Souping Up The .338 Winchester Magnum
Q: I was disappointed with the velocity I got from my .338 Win. Mag. with standard short magazine and deep seated bullets so I sold it. The best heavy bullet loads I found for it were the 250gn Barnes with 65gn of AR2209 which got just over 2500fps. This for the 250gn bullet deep seated to just fit in the in the standard short magazine. The Barnes 225gn TSX FB did a little better yielding 2710fps ahead of 71gn of AR2213SC. I used magnum primers and these were very accurate loads that averaged around 1.25 MoA. I did try the Woodleigh 300gn RN SN but although it was superbly accurate, velocity limited its range. I thought of buying a .340 Weatherby Magnum, but ammo and cases are quite expensive whereas .338 brass is reasonably priced by comparison.
A mate told me about the fine performance of your .338 Whitworth Express, but we couldn't find the issue of Sporting Shooter with the write-up. What can you tell me about it? If it appeals, I'll have my old worn Mark X Mauser .375 H&H rebarreled for it.
A: My .338 is built on a Whitworth Mark X Mauser action factory lengthened for the .375 H&H. It has a long magazine, so you are in with a chance. My rifle was throated to permit seating long bullets out with their bases flush with the base of the case
neck. The barrel has a 1:10 twist which is fast enough to stabilise the heaviest .338 bullets. I rely on just one good load that's proved effective on everything from red stag to water buffalo, moose and grizzly bear. I load 75gn of AR2209 with the Barnes 225gn X-Bullet for 2912fps. This is not only wonderfully accurate, but gives this bullet the same velocity the .340 Weatherby gets with 82gn of the same powder. Two other good loads are: 200gn Speer with 78gn of AR2209 for 3035 fps. and the 250gn Sierra BT and 77gn of Reloder 22 for 2820fps. Magnum primers are best with these heavy charges of slow burning powders.