Another fun game of round comparison, this time pitting the ferocious 338-378 Weatherby Magnum and the military favored 338 Lapua Magnum. If you’re looking at these two rounds, the 338 RUM and 338 Edge are both worth looking at as well, but for today, I’ll just be focusing on the Lapua and Weatherby 338’s.
The Lapua comes with a case capacity of 114.2 gr of water, while the 338-378 Weatherby holds 9.5% more at 125 gr of water. That 9.5% more capacity does translate into faster speeds. The Lapua has a slight advantage in that it isn’t a belted case like the big Weatherby is. Functionally, it doesn’t matter a whole heck of a lot, but it can be a bit more troublesome when it comes to reloading the cases. It should also be noted that the 338 Lapua has a gentler shoulder that should translate into slightly better feeding. Indeed, the 338 Lapua was made with semi-automatic firearms and their careful feeding requirements as a consideration. Not that you should have any problems feeding the 338-378’s double radius shoulder case from a more typical bolt action rifle either. These are both big, long rounds that feel more like artillery than a rifle. Case availability on the 338 Lapua is OK, with fantastic quality Lapua cases fairly readily available. Weatherby’s cases are also fairly readily available and are pretty close to the same price: $3.50/case for 338 Lapua vs $3.50/case for Weatherby 338-378 depending where you pick them up from. Both of these cases are high quality, and the cost of firing these big rifles means that any cost savings on brass is negligible.
Which cartridge to go for is largely a question of rifle. The mere 10% difference between the two cases is not much, but the difference in style of rifle is great. 338 Lapua Magnum is typically used in heavier tactical or target rifles such as the PGW Timberwolf, TRG-42, Accuracy International, McMillan TAC-338, Savage 110BA, or Remington MSR but there are a few rifles that could be hunted with. Savage’s relatively inexpensive 111 Long Range Hunter, the Remington 700 XCR Tactical or 700 Police, or even the McMillan Long Range Hunting Rifle could be used.
Here’s one funny thing about Weatherby, they’re chambering a lot of their rifles for both 338-378 AND 338 Lapua. That includes their hunting oriented Mark V Accumark as well as their tactically minded TRR. Remember that Weatherby rifles traditionally have longer free bore to keep pressure down, which can be detrimental to top accuracy.
Any rifle firing these rounds with a muzzle brake will require hearing protection worn even while hunting, while unbraked models will come with gobs of punishing recoil.
338 Lapua vs 338-378 Weatherby Ballistics
Finally, the gory details. What does that extra 10% case capacity buy you? Numbers obtained from Federal (338 Lapua) and Weatherby (338-378 Weatherby)
338 Lapua with 250 grain bullet: 2950 fps at the muzzle
338 Lapua with 300 grain bullet: 2580 fps at the muzzle
338 Weatherby with 250 grain bullet: 3060 fps at muzzle
Now that 100 fps won’t make spit for difference in the 250 grain partition because its BC sucks so much, but if you’re going long range and firing a slippery Berger hybrid OTM, that extra velocity will translate into some extra range for the Weatherby. It also comes with some extra recoil but with rifles at this point, who’s counting?
Into the Future
If you’d have picked up a catalog from Cabela’s 5 or 10 years ago, you wouldn’t have seen any 338 Lapua rifles listed but you may have seen the Weatherby. These days, it’s very different. Military acceptance of the 338 Lapua as an extended range sniping round has increased civilian interest and now there are lots of tactical and hunting rifles becoming available in 338 Lapua. As a big bad round capable of taking big game from a distance, it’s growing in popularity faster than the 338-378 Weatherby, and in the near future it looks like it’ll become the more popular choice.