• The .378 Weatherby; The Magnum's Magnum

    I've wanted to write an article on the mighty .378 Weatherby for some time, but felt I lacked the experience with the cartridge to do it true justice. One of our members, Wbypoor (Glenn), has added his wealth of experience with the .378 to this article supported by 30 years of use, which is more than anyone I know of and, as co-author, certainly adds considerable depth and breadth to this important cartridge in the Weatherby line-up.

    For those who must have the most of everything, there is the .378 Weatherby Magnum; truly a magnum’s magnum. Isn’t it interesting that when discussing the merits of the 378 the first thing to tackle is the recoil rumor? It leaves precious little space to discuss the history of the cartridge, how and when Roy developed it, and the fact that Federal developed a special primer just for the project.
    Yes, the .378 Weatherby will generate considerable free recoil, an average of 77 ft. lbs. from a 9 lb rifle. This compares to 20 ft.lbs from a rifle chambered for .30-06 Springfield, but is only 10% more than the recoil of the .375 H&H Magnum while having 22% more energy. There are some shooters who can handle recoil extremely well. Not because they don’t feel it, but because they know the recoil is coming and they can go right ahead and squeeze off a good shot. When some joker tells you he never feels recoil, he is either too dumb to be walking around, or he is a damn liar. There are an awful lot of hunters who are scared stiff of recoil and just plain can’t help it, some admit it and some don’t, but you’d just as well face up to it and either learn to whip it or shoot something you’re not afraid of. The .378 has less recoil than almost all cartridges of its energy class. While the recoil is stiff, exaggerations have likely done a lot to reduce the popularity of this caliber. Case in point: The Hodgdon Data Manual No. 26 describes it as, " . . . far too vicious for all but the most seasoned shooters." The Barnes Reloading Manual No. 1 reads, "This cartridge will develop literally tons of energy, but it is also known as perhaps the hardest kicking round there is." In fact, most of what you hear about the recoil of the .378 is purely exaggeration and usually comes from those passing along Old Wives tales. Here’s how I look at it: Currently there are 5 Weatherby cartridges based on the same case: the .30-.378, .338-.378, .378, .416, and the mighty .460. Some say that the recoil of the .378 may make it the hardest recoiling rifle on the planet because of its recoil velocity. Others say that it’s the hardest kicking of all Weatherby’s cartridge creations. Thought through logically, none of this makes any sense at all. Why would it? There is no magical property about the middle child in the big case line-up that makes it recoil harder than factory loads on the same case that are smaller, and also recoil more than factory cartridges on the same case that are larger. Recoil progresses as Newton predicted as you move up through the line-up from the .30-.378 to the .460. Period. Here’s what Glenn has to say about this: “Whenever a fellow shooter hears I’m shooting a 378 they invariable begin shaking in their boots! I don’t know who started the misguided rumor that by some voodoo the 378 is an unmanageable beast but I remember reading about it as a young boy. My first Mark V was a 460 and when luck finally brought cash and a good used 378 together I had a great opportunity to tangle with this beast. Imagine my great surprise when I found it was just like any other cartridge and behaved accordingly. Interestingly those who have not read of the 378’s reputation as a kicker find it easily managed. Even my 71 year old father finds my unbraked DGR easy to shoot ,but balks at a M77 in 416 Rigby and a 416 Ruger No. 1. Personally I find that those so straight combed rifles (classic? I think the Mark V is a classic!) generate more felt recoil than they should. I had a custom No.1 in 378 some years ago that punched the shoulder much harder than a Mark V, at least for me”.
    Moving past that, I have always been enamored by the .378 Weatherby. I also hold the same fascination with the .340 Weatherby. Something in their names just do it for me, I guess. An argument can be made that they are the two most versatile worldwide cartridges in the entire Weatherby family. I would be one to support that. In the same way that the .340 is the .338 Win. Mag. on steroids, the .378 is the .375 H&H on steroids. As one can argue that the .338 and .375 are extremely versatile cartridges for anything worldwide, the Weatherby variations make it even more so. The same can be said about any standard cartridges when compared to its Weatherby counterpart. Although the .340 and .378 are versatility kings, there are noteworthy differences. Glenn supports this by saying, “The 378 reaches similar velocities with larger diameter bullets; giving the 378 the unique ability to simplify shots to 400 yards when needed yet qualify as a dangerous game rifle in the African jurisdictions that restrict hunting dangerous game to rifle above .375 caliber. Of course the newer Remington 375 Ultra Mag can fill this role as well, 50 years late. Though very versatile, unfortunately the .338 caliber cartridges cannot meet the DG restrictions thus could never be considered a sound choice as a single rifle for a world wide hunter….Very few cartridges can match the 378’s effectiveness at a quarter mile”. While it shares the same bullet diameter as the .375 H&H, the velocity is in a different realm; the .378 pushes a 300 grain bullet at close to 3000 fps. That is an amazing statistic by anyone’s standards.
    And so it is with the .378 Weatherby. While the .378’s prowess against dangerous game has been highly touted, it’s greatest potential has almost been overlooked. With a trajectory comparable to a .340, and double the horsepower of a .30-06 at any distance, the .378 becomes an extraordinary long-range cartridge for any rifleman pursuing elk, moose, big bears, and larger African game. The .378 Weatherby is a monumental cartridge in its size, power, and capabilities. While the statistics of the .378 are heroic, Glenn reminds us, “As we’ve read, there are many stories floating around the big game hunting circles of the 378’s bullet failures on heavy game. With any cartridge bullet selection is always critical, even more so for dangerous game and high velocity cartridges. All of the troubles associated with the 378 can be directly traced to the root cause of using improper bullets for the quarry. Since the introduction of the Barnes X bullet and its later evolutions, the 378 has come into a world of its own. The effect of a high velocity 375 caliber bullet on flesh and bone is devastating and gone are the worries of bullets self-destructing. Shoot these 375 Barnes mono-metal bullets as fast as you wish, they will not fail. Neither will the 378”.
    There are many who consider this their favorite Weatherby cartridge. My favorite is still the .340, but I’d welcome the chance to see if the .378 can replace it. Well, not really, but I think it can be a valuable addition. A .270, .340, and .378 Weatherby would make for a very well rounded trio. Top it off with a varmint caliber and a charge stopper, and you’d have it all.
    I like this quote best from Weatherby himself when it comes to the .378 Weatherby Magnum:

    "Because there was a definite need for a large bore, heavy bullet traveling at high velocity, we developed the .378 Magnum. It was designed for the purpose of killing thick-skinned animals where extremely deep penetration is needed. This is truly the rifle for the man who wants the utmost in killing power when concentrating on the world's largest and most dangerous game."

    Another quote from Glenn is a fitting way to end this article about the Magnum’s magnum:

    “….I can’t help but get excited about a cartridge and rifle I’ve been using for 30 years now. In fact as time has passed I have learned to enjoy the 378’s notoriety as the big bad boy on the block, it always makes me chuckle when I seem them shaking like the world might stop spinning when I pull a 378 out of the case….”
    Comments 60 Comments
    1. 378Canuck's Avatar
      378Canuck -
      Love the 378, been shooting it for over 40 years now hope to shoot it at least another 10 years, then hand it over the next generation.
    1. Marine24's Avatar
      Marine24 -
      Old thread but couldn't help chiming in. No experience with the 378 Wby, but do with the 338 Win Mag, 340 Wby and 375 H&H. Comment about straight combed rifle is key. Shooting a friend's Ruger M77 in 338 Win Mag and my Mark V in 340 Wby with similar production ammo, the 340 Wby was more comfortable to shoot off the bench than the Ruger.

      My CZ 550 in 375 H&H isn't a significant leap from the 340 Wby either in felt recoil for me but like the Weatherby, the stock design seems to be key. My desire for a Ruger Nr 1 in 375 H&H quickly disappeared after shooting it once.

      Now a 378 Wby running 235gr Barnes TSX sounds like a very interesting long range hunting rifle. Thanks for the article. Might just have a new project in the making.
    1. dråparn's Avatar
      dråparn -
      I really Love the 378, IT served me well this year too. Okt 16 at 08,30 i shot a bull moose at 47 m that was comming right at me , and next min a cow and two calfs was running at my left side at 160 m so i took both calfs too. And yesterday i shot a cowmoose with my 460 wby. The season is not over yet so maybe i can drop another one
    1. gator378's Avatar
      gator378 -
      It is on my wish list. I am 67 and starting to save for the 378. It can not kick much worse than 1 oz slugs out of a 870 12 gauge.
    1. dråparn's Avatar
      dråparn -
      I wish your Dream come thru, the kick isnt so bad.
    1. gator378's Avatar
      gator378 -
      My dream is to have a 378. someday.
    1. 340 Weatherby's Avatar
      340 Weatherby -
      Quote Originally Posted by gator378 View Post
      It is on my wish list. I am 67 and starting to save for the 378. It can not kick much worse than 1 oz slugs out of a 870 12 gauge.
      Sorry, but without a AccuBrake the 378 is a lot worse. But just relax and enjoy it.
      To interpolate recoil, try out my recoil calculator. Can be found under the software menu.
    1. RobertRuark's Avatar
      RobertRuark -
      Ordered a 378 Mod. 2016 with the LXX trigger. Great forum, thank you!
    1. Wbypoor's Avatar
      Wbypoor -
      Quote Originally Posted by RobertRuark View Post
      Ordered a 378 Mod. 2016 with the LXX trigger. Great forum, thank you!
      Good luck with that new 378! Be sure to let us know how it performs for you.
    1. Downeast's Avatar
      Downeast -
      I wonder how the 378 Wby stacks up for LR shooting? We are building a 1200 yard range and one of my friends is pondering the .338 Lapua. I just don't know if the accuracy is there in this cartridge? I would invest in a 378 if it (and me!) can hold a 1 MOA out to 1,000.
    1. robert6715's Avatar
      robert6715 -
      I think the 378 loaded with 350gr Sierra match kings would be a fine LR rig. Not as many LR bullet choices for .375 bore.

    1. Bootes's Avatar
      Bootes -
      Hello ,
      does anyone have a rough idea how many were made by S and Larsen in 378 ,i thought they were only used by R.WBY for test beds for 378, not production rifles .
    1. dråparn's Avatar
      dråparn -
      The 378 wby is still my favorite, the last fall IT dropped 4 mooses drt, and one beaver one week ago. Took one moose with the 460 also.
    1. JB257460's Avatar
      JB257460 -
      Does your .378 have an Accubrake? It's funny, even though I've shot the .460 off of a bench, and also my current .416 Wby to sight it in, the .378 still seems more intimidating, even though I've never fired one. This is due to those ignorant gun writers who claim it's the most fiersome rifle to shoot....... of course that is B.S. I need to re-read the article I wrote 😂
    1. Bootes's Avatar
      Bootes -
      Got myself another 378 ,German which was the one i wanted, had opportunity for a jap one ,but paid the extra to get what i wanted ,i sold my last 378 which was an Accumark rebarreled to 378 with vais brake , i shot about 40 or more water buffalo with it ,5 wild cattle and some pigs ,most memorable shots were one buffalo at 200 yards, one shot pole axed him ,the other were two buffalo in some bush, i was with another hunter who had a 375 h and h ,we jumped out of the 4x4 and with two shots dropped i both buffalo ,the other hunter exclaimed ''THAT 378 !!!!!!!!!!!!!!!!!'',i dont know whether he was impressed or disgusted [no time for a shot],i wont be selling this one, not ever !
    1. dråparn's Avatar
      dråparn -
      Yes both rifles have accubrake from factory. I dont have any problems with shooting these big boys. Im invited to Hunt wildboar in two weeks so i Will take my 378 for the job.
    1. dråparn's Avatar
      dråparn -
      I have a hard time to understand why people fear the 378. I am not a big fellow, 168 cm and 63kg. I shoot my bees with joy. Happy shooting to you all/dråparn
    1. JB257460's Avatar
      JB257460 -
      Quote Originally Posted by dråparn View Post
      Yes both rifles have accubrake from factory. I dont have any problems with shooting these big boys. Im invited to Hunt wildboar in two weeks so i Will take my 378 for the job.
      Perfect! If I had a .378, I'd use it for my next boar hunt. Instead, I'll be bringing my .375 H&H
    1. dråparn's Avatar
      dråparn -
      The 375H&H works fine,i had 375 H&H for iver 25 years before i ordered My 378. Now i am looking for a third wby, probebly a 300.
    1. Bootes's Avatar
      Bootes -
      From what i can find there were eleven,Factory S and Larsen 378 rifles ,one for sale at the moment for $3000.00 US ,whether Roy Weatherby bought actions from S and L, or complete rifles [in another calibre 7x61] for testing ,when developing the 378,there is a B Grade movie on You
      Tube called ''The Last Dinosaur'' which has a rifle that appears to be a 54 J, S and L in a large cal possibly a 378
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