Home Forums Hunting & Shooting Express Rifles and Big Bores Only .378 Weatherby

Does anyone load for the .378?
I have a U.S made Euromark and looking for suggested starting loads for the 300gr Accubond.

Thanks!

Hello Boomer,

Nosler does not show a 300 gr. Accubond in the current #6 manual for any .375 cal. They do show the 300 gr. Partition bullet. The only Accubond for .375 is 260 gr.

Steve

That's a nice rifle. Why not visit the hogdon site and pick one of the 300 gr bullet starter loads?

http://data.hodgdon.com/main_menu.asp

If you're not looking for maximum punishment, selecting a safe starter load should be easy.

My bad...I was thinking or not and looking at 340 mag. Yeah go to Hodgdon....its late

102gn H 4831 with 300gn Swift A-Frama for 2650fps (mild easy shooting load)
111gn Rel 22 for factory specs around 2930fps
113gn Rel 22 for MAX and just over 3000 fps.

The 4350 work well with the lighter bullets as does H4831

Reduce loads 5% and work up please.

JW

Many thanks for the load suggestions.
The thought of a 300gr at 3000fps is exciting

Ian

I use a 375 H&H for NA bears but traded a few years back for a German Mark V in 378 Weatherby with a Pendleton brake,,,in case I one day made a trip to Africa for Cape Buffalo...I have read a lot about this caliber but no experience with it...what combos do you 378 users recommend?? In my 375 I use the 275 Bitterroots and WW 760 with Federal 215s in WW cases...I have read in Hagels writings the Norma/Weatherby is softer than Winchester...any comments??

I only have a .375 Wby, but if I had a .378 Wby, I would really want to try out the 350gr TSX, which has a B.C. of 0.425. I assume you could get about 2,700-2,800 fps out of it out of a .378, which would be pretty wicked against really big things.

Thanks...I think you are right on target with your velocity...102 H4831 shows to be 2779 to 2653 in Hodgdon and Barnes manuals....I think I'll get to work with the 350 TSX and see what happens...

The 378 is a superb caliber and like all weatherby calibers, they "outran" bullet technology at the time. I can't remember how many times I've heard (or read) "Weatherby calibers spoil too much meat, don't penetrate etc." All true thirty years ago maybe. With today's super-premiums like the TSXs the 378 is an incredible killer far out-pacing the 375s. Recoil is pretty stiff though. It comes back very fast and you need to hold on, but th result on game is devastating.

This is the albiet limited data I haev acrued using 2 different .378's.

JW


Bullet Load Powder O. A. L. Velocity Energy Comments

220gn Hornady 114gn IMR 4350 3380 5582

235gn Speer 112gn IMR 4350 3336

270gn Hornady 115gn H 4831 3142 AR 2213 used
117gn H 4831 3178 6057 AR 2213 used
117gn H 4831 2998 Original Surplus Powder
108gn IMR 4350 3150

300gn Hornady RN 102gn H 4831 2650 AR 2213 used

300gn Swift A-Frame 111gn Rel 22 2928
113gn Rel 22 3006 Warm Load


AR 2213 is H 4831
NOTE: that teh Origianl Surplus 4831 is designated separately.

Because the tSX essentially at worst turns into a solid no matter what happens to the expaonding front, that 350gr at 2,750 or so would be good, IMO, at the least, on any game not exceeding 3,000 lbs--and maybe more.

If you sight that in 3" high at 100 yds, it's only 5-1/4" low at 300 yds and has the same kinetic energy at that range as a 300 Win Mag does at the muzzle.

Wicked.

FWIW, I get 2,830 fps out of the 300gr NP loads in my .375 Wby. But it weighs about 11.5 lbs including a mercury tube in my MkV DGR. It recoils less than my Rem 700 .300 Win Mag. It's a bit hefty, but I;m in shape enough to carry it.

The 350gr out of the .378 Wby seems like an almost-unbeatable combination of speed, weight, mass, and down-range ballistics.

thanks for all the input re: 378 Weatherby...anyone use the Hawk 350 for NA hunting??

Load lightly.LOL
I had two buddies that had/have 378s and their shooting deteriorated conciderably compared to before they had them.
One fellow got a muzzle brake and that helped but the blast from it was terrible while hunting.
My question is can a 378 be loaded down to 375 H&H level without having to worry about hangfires? The 378 is nice but I would want one only if it could be loaded down.

This is a load only 100 fps more than the same bullet loaded in the .375 Wby, which is very pleasant to fire in my 11.5 lb .375 Wby DGR rifle. Weight makes a difference. I would not hesitate to man up and carry around and shoot a 11-12 lb Mk V .375 Wby, but I would rather drive nails into my forehead than fire a 7.5 lb .378 Wby.

Yep, that's why I sold the 378 and kept my 375Wby

Had a buddy who shot three scopes off his 378. He finally put a brake on it, but you did NOT want to be standing anywhere near when he touched it off.

I used to also own a non-braked 378 and the recoil could be described as very fast and if you had your eye too close to the scope it would have drawn blood for sure.

Boomer - Curious if you kept the rifle -- and if you still had any friends left if they stood next to the muzzle brake when you fired?

Mike378 owns 4 custom shop .378's. He is the Grand Poobah with this cartridghe as I know he owned at lease 2 more before these beauties arrived.

JW

A friend from law school's father was/is a Weatherby nut.

At the time we were visiting, his Dad had one in every Weatherby caliber except the .416.

We, of course, shot them all. The .460 knocked me backwards and was incredible, but manageable with it's weight and the recoil being just slow enough to be handled.

The .378 (not scoped, straight factory rifle) hit me so hard I couldn't see straight. It had nearly the recoil energy of the .460, just MUCH faster.

I decided then that unless one of those was vehicle mounted, and/or they resurrected sauro-lizards, I'd never again find ANY reason to shoot one of those cannons.

I've no doubt that they can be, and are, devastating on game; but wow....

The 378 Wby is beast!

I have a friend from UAI and he has shot a ton of buffalo with a the 375/404, the same thing as the .378 Wby balistically and he does a great job of killing them..I have seen him kill at least 40 buffalo with it and monolithic bullets of his own making. He is one hell of a good shot and a excellent hunter.

Saeed's 375/404?
It is more of a 375 Rum not a 378

According to Barnes manual #4, the difference between the .375 RUM and the .378 WBY is minimal at best...

Bob

www.bigbores.ca

I'm kind of liking this load.

I got my Mark V not too long ago. It's certainly the prettiest rifle I've ever owned and was lighter than I expected; certainly lighter than my CZ 550 Safari Magnum. I have to say, I like it quite a bit.

Very nice shooting Grumulkin!

I can tell you that it is about 150 fps in real life. I have worked on quite of few of each for a long time. For some that is minimal for others not.

Great shooting. Any idea on velocity?

I haven't chronographed the load yet so purely from educated conjecture, I would say about 2,900 fps.

Hi!

Had a WBY MK-V in .378 WM for years. Shot a couple of moose with it. 270 grs bullet load: 115 grs Rel 22,Fed 215 primers, cronographed 3100 fts.
300 grs Swift/Nosler part. load: 112 grs Rel 22,Fed 215,chronographed 2935 fts. All loads very deadly!!

By the way..made it a .460 Wby.

Great shooting but the holes are so small ...

Now THAT makes sense!!

Bob

www.bigbores.ca

Right on Jorge. I use the 300TSX with 114 grains of 7828 SC Fed 215 and clocking them at 3065-3090 fps. 0 at 100yds and 1 3/4 MOA at 300yds. Hang on tight to the wooden part. Haven't clocked the 250 grainers with 116 grains but they are humming along L'll bet. What was that about the RUM?

When I think of ballistic differences, I find it most useful to think in terms of percentages. A 5% difference is - to me - always a "minimal" difference. In most things in life, I think we'd be hard pressed to actually observe 5% differences.

A 5% difference on velocity is 10% on energy.

300 Savage, 308, 30-06, 300 WSM, 300 Win, 300 Wby, 300 RUM and 30-378. If we start at the 300 Savage and work our way up will there be some point where see a difference?

Obviously - eventually a person notices differences.

I'd suggest ACTUAL differences seen in trajectory (in field conditions) and in killing power would be unnoticeable - unless one could compare thousands of animals deaths, side by side, under identical conditions - with a 150 fps difference in muzzle velocity. I doubt even a lab could even quantify the differences we're talking about here - with an extra 150 fps. And - even that difference only exists at the muzzle - it's quite a bit less at distance.

Would you be able to tell if the car that hit you was going 27 miles an hour - or 28.5 miles per hour? Or even a full thirty miles per hour? Would anyone?

That's the percentage difference were talking about here.

One gets huge recoil differences - for very little velocity difference - at the high powder capacity end of the shooting spectrum. When a rifle recoils 50% harder - we humans note that it feels far worse for us - and we therefore expect the game to feel a huge difference too! But the laws of diminishing returns have already kicked in.

The huge recoil differences WE feel, doesn't equate to huge differences in killing power - or trajectory - or bullet speed - for any animal getting hit. Many shooters have noted how small the actual, measurable, differences are when noting what happens at the other end.

In fact, I'd suggest that after a lifetime of shooting the rifles you mentioned - one would be hard pressed to ever notice a quantifiable difference in killing power, between any two of the cartridges you listed, that are side-by-side in your example. You might well be able to notice recoil differences though.

You are probably right Brian. But since Weatherby brought their Mark V action in 1958 and Remington brought their RUM in 2002 it would seem that one would have more customers than the other.
Believe me I'm not goin out and getting a copy cat come late Rem that is trying to take business away from already a saturated market. The Mark V is said to be one of the strongest actions in the world so why go for second best or third best.

Brian

You correctly mention recoil and recoil illustrates thresholds. Anyone who has shot 375 and bigger a real lot will of course have noticed the gap from 375 to 458 is much bigger than 30-06 to 375. Yet the 375 is twice the recoil of a 30-06 and the 458 only a 1/3rd great than the 458. Increase the 458 by another 1/3rd to stuff like 416 Wby without the brake and the recoil felt seems like about 10 times as much And it is not just in the mind but sore neck, headache and so on.

If a rifle has .25" of freebore and we double it to .5" we might have increased the distance from ogive to lands by 11 times, that is, we might go from from .025" from the lands to .275"

I think similar happens with both bullet weight and velocity with animals. Of course I ma not saying it specifically happens at the 375 RUM and 378 level. A friend of mine, who posts here, has been to Africa many times and shot many buffalo. He has several Echol Legend rifles one of which is in 375 Wby. He chose 375 Wby over the H&H because of couple of trips with buffala and seeing his 375 H&H being used side by side with his mates 375 Ackley Improved.

Lastly, there is the "its in your mind" aspect and that is important. We tend to do better with calibre/rifle combinations we like. We see the good and not the bad etc.

Besides I like the cartridge box better. This one has been to Africa and back. LOL

Ah, the elephant packs. I had those with my first 460

I wish Wby kept those packets as well as the tiger etc and also those catalogues they used to sell way back in the 60s,70s

I agree with you all the way around. I've used the 378 for several years now and find both the cartridge and the Mark V to be fine performers. The performance of the Barnes TSX bullets is outstanding; the stories of viscious recoil largely exaggerated. In fact, if I had to choose one rifle and cartridge combination to hunt the globe, that would be it. Not perfect for many things, but perfect for anything.

It would be great if Barnes got off their buttocks and made a high BC TTSX for the 378 Bee instead of those cast-bullet BC look-alike TSX's!

Been begging for years now!

They got another e-mail from me this week. Once a month religiously!!!!

What seems to be holding Barnes back on this bullet? Lack of demand or lack of technical ability? I have zero issues with the 270 TSX to 400 yards or a bit further but it would be interesting to see what a true long range bullet would do out of the 378. It might surprise quite a few riflemen.

Good luck on your quest...

I think the US manufacturers have drawn the line at the 338 caliber. The TTSX, swift Scirocco, Interbond etc etc
Anything over they see as a close quarters hammer. Brown bear, buffalo etc.
That was the case of yesteryear but with the 378 Bee, the 375 RUM and others they need to offer something else to exploit the long range capabilities and power that these rounds can offer.
Heck I would even take a nice 375 300 grain VLD for most big game! And yes I asked for that too......many times.

Now if the get the GS Customs rolling here in the US then I am in! Can not really afford them shipped from South Africa.

Perhaps with a dash of good luck we will see the bullets you seek offered for the 378. I'd like to try them myself and still have a few hundred of the Sierra 350 grain MatchKings to play with, though I wouldn't presume to hunt big game with them. I would imagine that eventually the big manufacturers will run out of other small calibers to play with and get around to the .375" stuff, maybe then Berger or Barnes will step up to the plate. Maybe it'll be Swift or Hornady.

Heck, maybe we could call Corbin and do it ourselves!

North Fork makes a .375 caliber 350g soft point now. One of those at 2700 fps would certainly make an impression. They don't list ballistic coefficient but their bullets have a great reputation for expanding over the entire velocity range and holding together and still penetrating at very high velocities. They aren't cheap though ...

http://www.northforkbullets.com/magento/bullets/375-350-ss.html/

I wonder about the 350's? I can launch a 300TSX at 3000+ ft/sec, what would I gain by the change unless the BC is extremely high and can compensate for the weight gain. Probably to get any real world gain I would have to go to a 30+ inch barrel and then I wouldn't have a carry type rifle any more. For the moment I will stay with what I got because I know the 300 TSX are deadly on large game and do a fine job.

Anyone looking for a Weatherby MkV Deluxe in 378? Brother has one of those for sale too, along with his 500 Jeffrey. Pm me if anyone is interested. The 378 has been modified with mercury tubes and had the finish dulled up.

They pretty have the same BC;s as the swift A-frames which is to say mediocre at best

BTW I did e-mail Berger for a 300 hunting VLD. The ultimate LR elk gun!


GS Custom makes a 300 gr HV wit a BC of .475. I can easily launch this at 3100 fps. I just can not afford $140.00 for 50.

E-mail from Barnes today!




I suggest they get a lot of email request for a tipped 375...... Help out fellas!

emailbarnesbullets.com

Keep it up Fotis!

I am trying like hell!
Same for a Nosler e-tip and a VLD

L'd try them out if they aren't 2 bucks a pop.

You could try the Woodleigh 350gr VLD. Those are monsters!

...not to mention your shoulder and fillings.

Here is the results of some of the 'old' 250 grain Barnes X's. I had bought about 400 of them as they were boattails. I had never seen them before and haven't seen them since. Bought them back in about 1994 or so. Unfortunately I am down to 11 rounds. They are backed by 144.5 grs of H4350 and of course Fed 215's. I am now reading and trying to decide what I am going to replace them with...
In all the years and elk I have shot the 250's I have only recovered one. It was on a bull that was quarterning away at 446 yards. It entered just outside the left hip and lodged about 10 inches from it's right ear. It weighed 236 grains and looked just like one of Barnes advertisement pictures.

Holy cow! What cartridge was this in? Or is that a typo?

Probably meant 104.5gr

Typo, big time. 114.5 is what it should have read.

Muzzle velocity? I am guessing 3200 fps?

10 shot string averaged 3248 fps. If there was a door prize I think Fotis would have won it! Anyone shooting the 260 Acubonds?

Curious to where you got the load data.

Back when I bought my first 378 in 1990 I couldn't find any load data for 250's so I split the diff between 235 and 270's. I then worked my way up .5 of grain at a time, two three shot strings. I watched for primers to get flat, consistentcy in velocity and accuracy. This was the load that didn't show signs of pressure, only deviated about 10 fps shot to shot, and was the most accurate.

Also, the most accurate bullet in the first rifle was the 250 Sierra boattail, but they exploded on animals like a varmint bullet.

Barnes No.1 give 104.0gr of H4350 as max in the .378 Wby with the 250gr X.

I have owned about 5 or 6 of them. Played with just about everything dealing with them that is out there.

I am currently trying out the accubonds. 114 -115 of either H4831 or RL 22 is in the 3150 fps range. Also 112 gr of VN 560 got them out close to 3200 fps. Please work up...


BTW Barnes #1 manual was extremely conservative.

10-4 Fotis, thanks for the start. Any testing with 7828?

Not yet (specifically with the 260 accubonds that is). But I would start at a leisurely 114 gr and work up.

Fotis,
There is nothing leisurely about 114 grains of medium slow powder.

John

Nic Pics ovishunter and like your 378. The big .375 really clobbers them at any range it seems. Good load developement methods.(lots of safety margin with the Mark V action.

That's got to be the Weatherby advert for next year. Good one.

Funny!

Fotis,
You should PM "Mike378", I think you would find him interesting.

John

John Even though I have a tackdriver 416 Bee, I still crave the 378.

Try them all, only makes the .460 stand out more.

The .375 is more .375 that you need,
The .416 is 7/8ths of the real thing.

John

North Fork makes 350g bullets in .375 caliber too ...

It simply hard to beat a .416 caliber, weather Rigby Remington or Dakota. They penetrate from tail to tusk on elephant.

And I hope the Weatherby will perform just as well...

Well guys just bought another 378 Lasermark (5 panel). I also ordered a box of Barnes 250 gr TTSX's BC of .424.
I will also try the 260 AB's.
I will advise on accuracy and velocity!

Fotis,
You will get your money's worth every time you squeeze the trigger. 300gn Swift A-Frame at 3,000fps is a good match for the 7mm Remmy with 160gn load. Now you just need the Remmy?


Have fun.

John

nope I have them all (more or less)

I will be using the 250 TTSX and 260 AB's though. Much flatter shooting!

Congrats on the new 378 Fotis! I'm anxious to hear how it performs with the new 250gr TTSX as well.

Will do!

Resurrecting this as it has tons of gold mine info. What's everyone's current go to loads for a stout 378 Mark V?

Several years ago I built a 378 Weatherby to take to Africa. It was built on a Defiance Ultralight action with a 23" Muller #4 barrel in a Mcmillan Mountain Rifle stock with magnum fill and a small single side-port muzzle brake. If I recall correctly, it was 7lb 9oz before adding a 1-8 Swarovski.

Leading up to the trip, I spent a range session doing load development where I fired 40+ rounds ranging from 235gr at 3280 to 300gr at 2975.

While my shoulder took a beating, the worst part was the concussion; I swear I had a headache for two straight days afterwards.

A friend ended up killing a cape buffalo with it using a 270gr Barnes LRX. I would NOT recommend the bullet for buffalo at 40yrs given the muzzle velocity of 3118fps as they badly deformed on the shoulder bones and did not penetrate in even a remotely straight line.