This is kind of a tough call. I consider the .338 Win Mag one of the 'best' cartridges for North America. Many people don't realize that the .338 WM shoots 'flatter' (and hits 'harder') than the 7mm RM. It's definitely "too much" for roe and smaller deer. It's
not "too much" for sika, fallow and reds or boar. Also, I
prefer the 180s, but they are more difficult to get to shoot straight in my .338. I mostly use Nosler 210s (because they shoot the straightest) and Hornady 220s. There's no need for anything heavier, but that doesn't prevent the macho types from thinking they "need" 250s and more.
As to species I've shot with my .338 Win Mag: sitka black-tail deer (
Odocoileus hemionus sitkensis, 200 lb live weight average), mountain goat (
Oreamnos americanus, 250 lb live weight), dall sheep (
Ovis dalli dalli, live weight 250 lbs,) caribou (
Ranginfer tarandus, live weight 450 lbs), black bear (
Ursus americanus, live weight 200-300 lbs), grizzly bears (
Ursus horribilis, live weight 300 lb), coastal brown bears (
Ursus horribilis, live weight 800-1200 lbs). The .338 Win Mag does NOT cause "extra" meat damage. The worst meat "damage" I ever experienced in my life was using 175-grain round-nosed 7mm bullets.
As with all "magnum" cartridges, it doesn't NEED to be loaded to max pressures. That said, there are other .338 cartridges that use smaller cases - .338-'06, (pretty much the same as the .338x63 or 64 or 65), .338-08 (AKA .338 Federal). (I have a .338 Federal. It's a fine cartridge.) Any of those would probably allow one to use the cartridge on roe and smaller deer. HOWEVER, I find it hard to believe, based on what I read here at the SD, that it wouldn't be an "uphill battle" to get a .338 caliber cartridge "allowed" for stalking. Too much ignorance about firearms by the "constabulary" and too much ignorance by stalkers about the cartridge. At the same time, a 9.3 caliber cartridge, .366" in diameter, would be perfectly "OK".
Once labeled "magnum", "we" all KNOW that ANY cartridge is just
devastatingly more powerful.
The .338 Win Mag is an excellent cartridge, especially among those cartridges with the "magnum" appellations. However, for both socio-political and practical reasons, I can't really see it as a viable cartridge for the British Isles.
Regards,
Paul