378 Weatherby Magnum

(12 customer reviews)


Designed to replace the 375 Weatherby Magnum, deep penetration and bone smashing power are the calling cards of the 378.

SKU: 378 Category: Tag:


Ammunition Shipment Restrictions

Must be 18 or older to purchase rifle ammunition. Shipping not available to P.O. Boxes, International Addresses, AK, CA, HI, MA, CT, IL, NJ, NY nor DC residents. Residents of DE, KS, OH, and WA may have additional restrictions. All ammunition is shipped domestic ground and an adult signature is required. We do not accept returns on ammunition.

Designed to replace the 375 Weatherby Magnum, deep penetration and bone smashing power are the calling cards of the 378. Its massive case holds so much powder that Federal designed its super-hot 215 primer to handle the load. Roy Weatherby’s 378 delivers 34 percent more energy at the muzzle than the powerful 375 H&H Magnum. Since 1955, the 378 has become one of the world’s most popular cartridges for the largest of big game animals.

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12 reviews for 378 Weatherby Magnum

  1. Wesley

    For those that think a 378 Weatherby Mag is too much rifle for small animals like Texas whitetail deer, you are completely wrong. The heavy bullets are hard to deform and use 1,000 of pounds of energy on the deer and 5,000 of pounds of energy on the tree or hillside behind it.

  2. LEITH Wimmer (verified owner)

    Great cartridge. Just sighted in my new MkV Deluxe 378. 3-2shot groups at 100 averaged .312 inches. At almost $10 per round I cut it short of 3 per group. I love weatherby rifles and ammo now. Won’t be reloading 378 with this level of accuracy. Well done Weatherby! Would be even better if the ammo was more reasonable $.

  3. Shawn (verified owner)

    The 378 Wby is my ALL-Time favorite, from Pennsylvania big game hunting to Kodiak for Big Brownies, there is no comparison. I have retired my 300 Winch Mag and 375 H&H, for there is No-Need for them!

  4. Massimiliano

    Simply the best big game cartridge ever made. The 378 Wby has the punch of a 500 NE and the trajectory of a 300 Win mag.

  5. Jesse Wiehahn

    African game are extremely tough to go down .. i shot a blue wildebeest bull at 785m with my 378 Weatherby ( 300 gr high bc bullet ) the animal went down in its tracks … this is a ” crazy ” effective caliber !!!!!

  6. johnny dawson

    Hand-load results: three shots under a quarter at a hundred yards with the Sierra 300 grain boat tail.

  7. Sawman

    When Life is on the line.
    Trust no other.

  8. Nick

    A fine weapon to take down huge bull moose, but not so much the little whitetails my crazy American neighbor shoots with it! I think the bullet field dresses whatever is left of it!

  9. Jesse

    As a long range caliber it’s hard to beat the 378 weatherby ..

    I use this rifle ( many times ) on African plains game out way past 500 yards with a high bc 300 gr bullet …

    This is my ultimate hunting experience ever !!

    Regards Jesse Wiehahn

  10. Tom

    One shot kills when hunting boar is guaranteed. Exit holes like the bottom of a beer stud.
    If you want just to “plink” around, 0,5″ groups of 3 shots at 100 yards are not uncommon if you do reloading with Barnes TSX bullets.

  11. dråparn

    10+ moose roebuck and beaver have felt the power of the 378. My favorite rifle

  12. Norbert

    It is the “what ever walks on this planet” cartridge……

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