338 Lapua vs 338-378 Weatherby

338 Lapua with 300 bergers and 250 grain GameKings

338 Lapua with 300 bergers and 250 grain GameKings

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 Case

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.

Available Rifles

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.

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  • Gio Brighi

    Dear Sir ,
    it’s me that years ago I suggested to Ed Weatherby to build a ” tactical ” gun for the 338-378 cartridge , I had reloaded it extensively and it had given me wonderful results both as a speed that as precision. I’m an expert reloader and I can state that the belted cartridge case of the 338-378 gave me no problem , as chambering and as head spacing . I reloaded the 338-378 with very slow Hodgdon spherical powders and I got speeds up to 950 mt/sec . This without excessive pressure and largely sub-MOA accuracy ! The Lapua cartridge , in addition to being aesthetically horrible , was also designed for automatic weapons ( huge body taper ) : it is one of many horrible compromises so prevalent among men ! But I ” understand ” the soul , the beauty and efficiency of a great cartridge , and I would never change my 338-378 Weath with the ” politically correct ” 338 Lapua !

  • Gio Brighi

    P.S. : 950 mt/sec with 250 grains bullets .
    Thank you !

  • Jenkem Jones

    338 Lapua loaded ammunition is less expensive (I wouldn’t call any of this ‘cheaper’.) . They are much bigger than I want, but I find it interesting.

  • Jenkem Jones

    Or 3,100 ft/s with 16.2 g bullets.

  • Travis Santelmann

    The .338 Lapua Magnum =2,850 FPS/ 4,560Ft Lbs energy.

    .338-378 Weatherby Magnum= 3,060 FPS/ 5,280 FT LBS energy.

    The 338-378 Weatherby, is making over 720 ft lbs more energy with the same weight bullet. And 210 more fps. That extra 720ft lbs of power, will really shine at the 1 miles/ OR, “1,760 METER MARK”

    Weather builds the hottest! You do not have huge rifle selection, and brass is costly!

    The Weatherby has only 10 or so choices in factory loaded ammo.. The cheapest being $110 for (20) rounds!

    The 338 Lapua has over 100 choices in factory loaded ammo. With some costing only $35 for (20)!

    And considering which would be more readily available in the field.

    The Weatherby is great none the less!

    But Lapua is only a little powerful, with much more availability!

    There is something I just love about Weatherby hot rods calibre’s though!

  • Nick Bunu

    can you please share your loading data?,i have been trying different powders at diverse loads,still not happy with grouping results.

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