338 378 Weatherby mag

I found an empty brass at the rifle range. Hadn't heard of it but it is a biggun.
Beside a 7mm. 30-06, and 308.

Pricey ammo too.
And people claim accuracy at 1500 yards.
I don't think I'd want to put that to my shoulder.

It's little brother, the 30-378 Weatherby is better known and slightly more popular. Claims to be the biggest non-wildcat 30 caliber. Both are a necked down from the 378 Weatherby Magnum parent case. Real powder hogs, they are king in their class but they burn a lot more powder for that last little bit of velocity.

I've never shot either one, a friend had a 30-378 that I wanted to shoot but he sold it before I got the chance to. Both and their parent are known for recoil, but most factory rifles are fairly heavy and that helps mitigate it. Did talk to a guy who was building a custom rig for a Dall sheep hunt, claimed it was going to come in under six pounds. Not sure how bad I would have wanted to shoot it!

Keep plenty of barrels on hand.

Mike

They say it weighs 18 pounds.

I had the 30-378 Weatherby . Shot it 5 times and said not for me . I do hunt with a 300 rum witch is very close to the same ballistics but not near the recoil and a little less expensive to .

I reload for my cousins 338-378. He can have it

That is a large and imposing empty case!

Team - how is performance of the 300 RUM on large critters?
My only experience with mine has been on whitetail deer.
Their size doesn’t let the bullet perform properly.
I bought mine because of some planned hunts for large game away from home.
Very impressive ballistics.
That year wifey and I both drew great moose tags.
Unfortunately wifey developed a very serious health problem and we had to cancel.

I have a couple friends with 300 RUMs. 1 of them hunts elk every year here in SD (landowner) he shoots a swift sirrocco 2 bullet I don’t recall the weight. He’s a great shooter and the gun performs fantastically dead elk every time.
The other friend bought his 300 RUM for a Canadian black bear hunt just because he could I guess. He shot a very large bear about 500 pounds if I remember correctly. No problems with it. He primarily uses it for mule and whitetail deer and antelope now. I load 180 accubonds in it for him. The only time I shot it was for some prairie dog excitement! Plenty of gun for sure.

I remember when the Ultra Mags came out, the 300 being by far the most popular. About half the guys who bought them loved them, and the other half got rid of them after shooting them a few times. A lot depends on the design of the gun, how the recoil is. Fast, flat shooting, they pack plenty of punch, but again they are powder hogs. A friend of mine has a 7mm Ultra mag, I was debating between it, the 300 RUM, and the 7mm STW I eventually had built. With light bullets (140s) the 7mm RUM will outshoot my STW, but with the big 180s I shoot out of my STW they were equal velocities shooting side by side over a chrono (his didn't have the proper twist to stabilize those long heavy bullets so they weren't accurate, but that is a gun, not a cartridge issue) but I was loading 20 grains less powder to achieve the same ballistics! And could carry one more in the magazine.

The 300 RUM is a very nice cartridge though and at least in this area not too uncommon so factory ammo can be found. If reloading for it pay attention to the bullets you are loading in it however, there are a number of 30 caliber bullets that are not designed to fly that fast and their performance on game is very subpar in the RUM, particularly at shorter distances. You need a bullet with a fairly tough jacket so it doesn't grenade on impact at high velocities. Can't speak to performance on the big bears, but performance on deer, elk, moose, and black bear is very good with proper bullets. I've guided a number of guys with them, as well as having numerous friends and acquiantances who use them. Even had my mom shoot a whitetail with one once, that was out of range for her old lever action 308. Only problems I have seen with them are some guys who can't shoot that big of a gun accurately, or handloads with inappropriate bullets.

I shoot a 30-378 weatherby , and have taken deer , moose , bear and caribou...
You must find a very good bullet design to take that velocity...
I handload and use scirocco 180 grain bullets

I shoot deer mostly now , and have found my 6.5x55 or my 7x57 to be much more user friendly..
My deer season starts tomorrow, and my Winchester model 70 supergrade in 7x57 will be my choice

I was asking about the performance of the .300 RUM on large animals because it has plenty of horsepower. My only experience with it is shooting a couple whitetails. I don’t load rifle cartridges so use Federal Premium ammunition. The bullet was a Barnes something which did not expand and seemed to zip right through without dumping much hydrostatic shock. Of course, the bullet was designed for larger animals.

Team V - do you have any experience with the .300 RUM on moose or brown bears?

ArcticOtter & Bearcat - those are tremendous reports about known experiences. Loading for it with those 180 Accubonds would make it behave. Prairie dog vapor?
You guys are experts on rifles, ammunition, and loading. I have always loved the science of loading and the ballistics of shooting. But with many outdoor passions and the gear, I just never could add in loading rifle cartridges. Recoil from the .300 RUM is certainly less than a 12 gauge 3.5” super magnum 2 ounce lead turkey load! Your mom must be very cool!

Slowpoke - I bet that 30-378 is a brute too! Good luck tomorrow and enjoy your classic rifle.

One thing people forget weatherby builds the gun around the ammo and the barrel is built to take repeated shots I have several of them, dad has a 300 from Germany and the barrel looks as good as a new one, if you want a kick try the 460 it’ll wake you up and when I reload that one, when I can find powder, I can just pour it into the brass with a funnel.

Have shot a ton of moose and caribou with my 300 rum from 40 yards out to 711 all dead . I found the 210 accubonds work the best and all bullets have past through and I have never recovered one . We’re we hunt it is mountain to mountain shooting. I have never shot a bear with it because most of my bear hunting is over bait and I use a bow or a 458 socom witch lays them out .

The 30-378 seems like too much of a good thing to me. Rather than shoot a grossly overbore 30 caliber I'd rather jump up in bore size.

I don't think Weatherby makes a rifle in that caliber without a muzzle brake. I bet the muzzle blast is fun.

You guys have great experiences!
Loading, ballistics, and hunting performance is great fun to discuss.
Thank you for the info.
I am ready and willing to go on any adventure if you ever want another person.

I had quite a bit of work done on my .300 RUM, including a custom muzzle brake.
The recoil is reduced by approximately 40% and the sound is increased about 40%.
The blast is tremendous! A threaded cap in place of the muzzle brake puts it back to original recoil and sound. Either way, ear plugs are essential.

Shot 180gr CoreLokts in a .300RUM for Whitetails and way way way over kill. The entrance was a normal exit and the exit was just way too much. I think a softball could’ve fit in it without getting blood on it. I shot one deer right at 100yds and it fell straight down, legs folded under him, and nose straight down in the dirt. I stayed on the scope because I’d never seen one drop like that. Decided I didn’t need it after that. Beyond overkill for anything we have down here.

Shot my nevada bull with a 300 rum at 275 yards he soaked up 4 shots before he went down. All in the bread basket good round no better or worse then what I've seen with 300wm.

Could be the gateway to your next rotator cuff surgery.

Wanna be - I agree completely that the .300 RUM is too much gun to hunt whitetail deer especially using factory loaded ammunition. The reasons are way too long to address here, but I did not originally select it to use for whitetail deer hunting.

Likewise the .338-378 would be even more extreme. I wanted to ask knowledgeable and experienced guys about their experiences.

I have a 30-378 and is my go to rifle. Extremely accurate and can get it done from 1 foot to as far as I can see. I've only taken 2 of those shots in 20 years outside of the range as the planets almost have to align for it to reasonable. I was successful both times. Mine is zipping a 180 at just under 3,600. I had a 338-378 and wish I still did. It was a great shooter and has more case capacity than the Lapua. I have been playing with a wildcatted 35 the last couple years I just loaded my ammo for the season yesterday it opens in the morning. I'm not gonna say what it is but it is loaded with 96.5 grains of RL9 pushing a 200 grain projectile. It is on an Encore frame and is ultra accurate.

You can do that with a 243 at 200 yds with a high shoulder shot on whitetail

That cartridge was devolved clear back in the 60s I believe, and so was the 30-378 I believe, it's funny how Weatherby never did anything with it for so long, Elmer Keith was one of the guys that did the wild cat back then.


338 KT