I've got the 30-378, with the AccuBrake. I still believe it contributed to some of the hearing loss in my right ear, from the first time I touched it off. Even WITH ear plugs. Won't be looking much beyond that for velocity and energy in shoulder fired armaments. If I can't kill it with that, so be it.

Got a 30-378 backcountry 2.0 carbon on order. Very excited. Was hoping to have it for this season but doesn’t look good..The recoil on them is surprisingly light with the accubrake.

These big powder capacity cartridges really shine in the heavy for Caliber bullets. 220-250 grain bullets for 30 cal and 250 -300 grain bullets for 33 cal. A good benchmark velocity for a hunting cartridge is a 2700 fps. Like.the 30-06 loaded with a 180 grain bullet. A very well proven killer of game animals. Once you get in the 3000 fps and up rang of velocity, conventional cup and core lead bullets are over stress with less predictable performance on game. One needs a balance of penitration and bullet expansion. The high velocity of 3000 + fps is good for long range performance but take note that past 300 yards how even the flattest shooting cartridges start really taking a dive. A 250 grain bullet in a 30-378 and 300 grain bullet in 338-378 would get the most from these big case capacity cartridges. Should be easy to get a good balance of penitration and bullet expansion. A Nosler Partition in those bullet weights would be idea for around hunting. For dangerous game you may need a tougher bullet.

Great video. Just ran across this. If a person can handle the recoil of a 30-06, they can handle a Mark V Accumark with Accubrake in 338-378. This cartridge is devastating on thick-skinned game. I'm pretty sure it could take an elephant with a well placed shot and a solid bullet.

I had a 30-378 built with a 28” barrel. It is not for the recoil shy. I sold it to a friend who still owns it. Between us we’ve taken whitetails, mule deer, elk, and moose. It may not be efficient but it sure kills in spectacular fashion.

Yes, you WILL GET 100fps (almost EXACTLY) more out of a 30” barrel with the .338-.378 Weatherby. I have two Tacmark Elites and one of them has the 26” factory barrel but the other one has a custom 30” Kreiger tube. It shoots every weight bullet 99.5 FPS faster.

Just got a 338-378. My best friend growing up dad had a 338 win mag and it was very accurate. Convinced me to buy the 338- 378 for hunting elk at longer range shots.

I got one of each. I had the 30-378 for a number of years and recently bought a new Mk V. I absolutely love the cartridge and have taken everything from wt deer to elk and moose, black and grizzly bears. I bought a second hand 338 - 378 just a few years ago and I was amazed at how accurate it was. I've only taken a black bear with it, but I am certain it kicks noticeably harder than the 30-378. I do like them both and hopefully I will be able to use them for more hunting in the future. I don't think you can go wrong with either one.

I will own one of these rifles someday hopefully next year

To get maximum speed out of them you would need a 42inch barrel

RW, cool comparison. Really glad to hear you basically toss "efficiency " out the window. Personally when I hear someone tell me about a cartridge's efficiency I lose interest in what comes next. Even though these two are king of the hill in their calibers I haven't yet found much reason to scrap my 300 Weatherby or 340 Weatherby. Since I don't reload, yet, ammo supple might be an issue, for me. On that case size I'm stick with one of my all time favorites, the 416 Weatherby. Oh, and as for barrel life, who cares. Everything wears out eventually.

It seams to me like the books are very lacking on these rounds. I get 3450 with a 185gr Barnes TTSX out of my .340 and it’s got a tight chamber and 26” bbl. I have always thought the 338-378 performance was a little disappointing for it case capacity. Maybe it’s because, like you said, it needs a 30” or even longer bbl. I will say though, during the pandemic, the one ammo I was easily able to find, was the 30-378. I tried to find a 30-378 for this reason and they were hard to get your hands on. All I could find were the POS Needmore and the PRC’s.

What ballistic program are using on MS Excel???

I've never noticed recoil while shooting critters.

My buddies have these rounds as their play around rifles lol they are shooting 375 Cheytac for long range, they are a different breed with all their extra money they make goes into their long range shooting and my buddies dad legit has the sniper school record, or used to, Id imagine that someone has beaten it by now. All the shots were hits but 2 and that's VERY rare because of the wind, but he had the best spotter and the spotter at the time was highly requested because he was a genius for looking at the flags and by really knowing that wind MPH by how the flag is moving! I have a Christensen MPR .300 Win Mag and its better then most people's rifles but 1/3rd of their scopes costs more then my whole set up!

Your shoulder! lol

They are both amazing rounds, but they're also just too much fun for my old bones, and I'd kind of like to keep my retinas where they are, not flapping around loose inside my eyeball.

I just went pure native with this one and got a .378 Weatherby with a welded on muzzle brake. The recoil is not an issue and with a 270 grain Barnes X it will flip a 700 pound Bull Nilgai over backwards at 150 yards.

I noticed something quite interesting for the first time recently... the .300 Ruger Compact Magnum... why didn't it pick up? It seems to me like it's a perfect 'not quite magnum'. I guess that might be why it failed - it sits right inbetween the giants of .30 cal.. perfectly smack bang inbetween .308, .30-06, .300 WSM and .300 Win Mag. But 200fps over the .308, but not the recoil of a Win Mag/WSM? Sounds awesome to me! 165gr going 2900-3000fps. I guess the same goes for .338 RCM.

So 3 Weatherby 378's i thought it was 2, you should have compared all 3 . I am actually wanting an early vintage Mark V in 378 .

.338 Norma Magnum is the Special Forces new sniper round that's going to be replacing the .300 win mag, and 50 cal for most uses! The 338 Norma mag can penetrate 1 inch of steel at 1500 yards with the special rounds!!! The military is also using the .300 Norma Magnum and of course the O.G .308 the pack comes with all 3 barrels, mags, and all the parts you need in 1 big ol bag in the Barrett MK22 it's a beauty!!!!! And it shoots lasers! Id love to see the .338 Norma battle the Ultra, Lepua, 33 Nosler and 338-378!!! The battle of the .338's!! My money is on the .338 Norma!!!!

Dont need a longer barrel, just make the twist 1:8 or 1:8.5 that will stabilize those longer rounds of the rocket propellent the fat brass is pushing out!

You forgot the warbird for comparison!

I owned a 30-378 and it was very impressive

Pay twice as much for ammo that only gives you maybe 200 fps faster than the 300 and 340 Weatherby.

I've reloaded 30-378 Weatherby rounds before, and I've gotten 3,900 ft/s with a 150 grain bullet!

Don’t the 33xc beat out these?

My Nosler book has the 338 sending a 250 grain bullet about 20fps faster than the 300 shooting a 220 grain bullet

Have you thought about doing a video without the book?

I have a accumark in 30-378 and a mark v action with a custom 28 inch hart barrel in 338-378 in my 338-378 i get 3200fps wit a 250 accubond it is a awesome cartridge i got my farthest kill with that at 840 yds on a spanish goat of the 2 i prefer the 338-378

Weatherby should chamber the Vanguard in 270,7mm and 340 Weatherby magnums.

This is like hunting with a anti-aircraft gun.

Don’t forget the 340 wb and 338rpm

Take off those muzzle brakes and let's see how long you keep one of these! lol

I have 338 rum 340 wby 338 lapua ai 338-378 and a 338 khan which is a 338-378 thats ackley impovd the 338-378 wby with a proper barrel will stomp every 338 cartridge period

I cant get any where near 3300fps with a 200 accubond in my 30-378 the best i can get is 3200 max and thats with 114 grains of h50bmg powder both rounds need atleast 28 inch barrel to shine i get 3200 fps with a 250 accubond and 7828 powder do the ballistics on that it will stomp the 30-378

In my 338-378

Just heard that Weatherby Mark V is on the banned firearm list in Canada. Some Weatherby magnums are more powerful than what they will allow so they are banning all Mark V. 😢