Loads for .375 Weatherby?

Hector,
What components are generally available to you there? (Bullets, Powders, Primers, Brass) Any specific game animals in mind? I have much load data for you. Email me.

[ 09-07-2003, 20:15: Message edited by: Nickudu ]

Aside from the mucho data Nick may be able to supply, I use only one load:

88.0 grains of IMR 4350
any 300 grain bullet
F215 primer
Winchester brass (.375 H&H fireformed)

Gets about 2700 to 2750 fps depending on the bullet, in my 24" barrel.

300 grain Sierra for soft/light game at long range, or

300 grain Swift A-Frame, Nosler Partition, X-Bullet, or any solid for tough targets.

One bullet weight and powder charge, KISS principle.

Next best thing to Saeed's .375/404, and it will certainly duplicate the performance if you are as good a "shottist" as Saeed.

One planet, one bore diameter.

Of course, know your amount of freebore and start low and work up, etc.

[ 09-07-2003, 19:55: Message edited by: DaggaRon ]

Mucho = Typo ... Sorry about that!
A single powder charge for "any 300 grain bullet"?
Questionable advice, my friend. You should know better.

Nickudu,
In my rifle it works well.

If we are trying to get the velocities of all these bullets the same, then you can fine tune the decimal grains.

Note the disclaimer to "Know Your Freebore" and work up with any of the Weatherby cartridges.

Especially a custom chambered rifle with minimal freebore, as the Weatherby factory ammo may be too hot, pierce primers, etc.

That is a great thing about the .375 Weatherby now, with properly headstamped brass available from Weatherby. I have two boxes of it, but will continue to use the excellent Winchester fireformed cases unless I go to one of those peculiar countries that require matching headstamps.

One powder, one bullet weight, and in the case of my rifle, one powder charge weight. In my case the 300 grain Sierra is most accurate with this charge, for deer and varmints and such. The tougher 300 grain bullets shoot satisfactorily at this charge too, at closer range.

Of course, this is my version of a KISS rifle.

The optimum powder charge with the various bullets may vary a couple of grains either way, but I am safe in my rifle just as I stated.

But, Nick, if you must KISS it to the max, then you are right, you are only allowed one bullet.

I suspect one could KISS it with RL-19 also.

KISS - Well O.K. but KISS powders should be those powders that are so slow for the cartridge at hand, that there's simply no way the "advisoree" can stuff enough in to get into trouble. IMR-4350 is not a KISS powder for this cartridge, IMO. My load data for the 300 grain monos in this chambering call for from 3 to 4 grains less powder than with the shorter, softer 300 grain bullets of less bearing surface and more conventional design. This comes from the loading of some half-dozen or so .375 Weatherby rifles, of various description and the general theme applys pretty much across the cartridgeboard.

Leaving now, to see my Granddaughter ... catch up with you later. ... N

You are certainly right about the safety issues and internal ballistics, Nick.

However, my use of the KISS principle refers to DEAR OLD SAEED'S USAGE:

KEEP IT SIMPLE STUPID

Which means:

One bullet weight, one trajectory to memorize, never fumbling around at the time for the shot.

So, y'all don't try what DagaRon does at home, do as Nick says.

Nickudu
We have all the IMR, Reloader 12 / 15 / 19 / 22 / 25, Hodgon 4350 / 4831 / 450 / 414 / 870 Accurate Arms 3100 / 4350 / 2460 / 8700 Norma 203 and local powders.
Bullets: Hornady 270 and 300 (solid and SP), Barnes 350 solid, Nosler Partitions 300 and Sierra 250 and 300 SP Spz.
I have two .375 H&H in 24 and 25" barrels (Mauser and Musgrave) and I shot more than 40 animals (Kudu, Nyala, Cebra, Eland and more in Africa) and others in Argentina with the Mauser 25" barrel. Now I have a new Brno CZ in .375 caliber, for convertion to .375 Weatherby.
Thanks for your answer and best regards.
H�ctor.

O.K. guys, I know the Weatherby freebore is a ticklish issue, but why not share some real life load experiences here? Any other .375 Weatherby Pet Loads?

Hector, you are very accomplished in Africa to be coming to the .375 Weatherby so late.

My first foray into supporting my local gunsmith was to have Willis Fowler of Anchorage, Alaska rechamber a Whitworth Mark X Mauser from .375 H&H to .375 Weatherby, then off to Kodiak Island to chase bears and shoot deer with it. I did not fill my bear tag, hunting with a buddy as resident drawing permit holders in Jap Bay. But I did drop a couple of Sitka blacktails, one on the run at 150 yards, piled up instant dead.

Now, I must complete the circle and have one more rechambered, and I think it will be a Winchester M70 Classic Stainless and/or a CZ 550 Magnum Safari???

The .375 Weatherby is better than the .458 Lott for being able to fire factory .375 H&H in a pinch, with good performance and no ill effects, versus the .458 WinMag in the .458 Lott, which may roughen the neck of the Lott chamber.

Yep, it has Saeed's .375/404 beat in that regard, being able to fire the ubiquitous .375 H&H, and being able to easily equal the ballistics that Saeed uses to kill everything that walks the planet, with authority.

My first .375 Weatherby has usual Weatherby freebore. My next one(s) may not, and may have to be carefully handloaded following Nickudu's proper techniques.

So to share some of my experience in loading, that others might learn, and to encourage others to share their loads, here is some real data by yours truly:

Factory .375 H&H loads fired first in a Mark X Whitworth Express rifle, then in a different Whitworth rechambered to .375 Weatherby with 3/4" freebore, both rifles 24" barrels, only three shots each average velocity, so of limited statistical significance:

270 grain Winchester Power Point:
H&H chamber ... 2751 fps ES 18 fps
Wby chamber ... 2611 fps ES 21 fps

300 grain Winchester Silvertip:
H&H chamber ... 2471 fps ES 65 fps
Wby chamber ... 2303 fps ES 40 fps

Some handloads for the .375 Weatherby, all using Winchester brass first fireformed (using 66 grains of IMR 3031, CCI 250 primer, and the 225 grain Sierra FN bullet, an excellent deer/varmint load and fireforming load of about 2700 fps in blowing out to the Weatherby chamber) then loaded with F215 primer and the below bullets and powders, 24" barrel, 5 shot averages:

235 grain Speer SS (no crimp)
86.0 grains IMR-4064
3086 fps
ES 32 fps
COL 3.520"

300 grain Hornady BTSP (no crimp)
88.0 grains IMR-4350
2746 fps
ES 11 fps
COL 3.562"

300 grain Sierra BTSP (no crimp)
88.0 grains IMR-4350
2742 fps
ES 13 fps
COL 3.606"

300 grain Swift A-Frame crimped on cannelure
88.0 grains IMR-4350
2717 fps
ES 18 fps

Now, when it comes to the monolithic Barnes solid and X-Bullet, I better not go there lest I inflame Nickudu.

Aw shucks, just a little kindling:

270 grain Barnes X-Bullet seated way out to end of magazine
90.0 grains of IMR-4350
2906 fps
Not for every rifle. Not a recommended load unless you have plenty of freebore and you are chasing game in chilly climes, like King Kong of Kodiak. Kills deer instant dead too, just for the record.

Daga ... you light my fire.

Hector,
Below are the loadings which were digested well by all the .375 Wea., to date. The "X" bullets were molycoated but were also O.K. without it. None were max loads but speed & accuracy were real good.

250 X � Moly � 89 Gr./ H-4350 � 215 GM � 3.625�
300 Hornady FMC � 85 Gr./ H-4350 � 215GM � 3.625�
300 X � Moly � 85 Gr. / H-4350 � 215 GM � 3.625�

[ 09-09-2003, 21:14: Message edited by: Nickudu ]

Nickudu's loads are definitely low pressure.

I would consider them starting loads in my .375 Weatherby.

Identical charges of H-4350 versus IMR-4350 gave about 100 fps less velocity in my rifle.

IMR-4350 will give higher velocities (and pressures) than H-4350.

IMR-4350 is slightly faster burning than H-4350.

But take this with a grain of saltpeter, as my comparison was done back in the mid 1980's.

Characteristics of new lots of IMR-4350 and H-4350 may have changed, but there is your ball park.

Thanks, Nick. Now grab the fire extinguisher.

[ 09-09-2003, 21:19: Message edited by: DaggaRon ]

Nah ... let it burn. It's actually kinda cozy.
What's that old term? ... "kindling spirits"?

350gr woodleigh pp
88.5gr h4831sc
fed215 primers
win.hh brass
vel. 2550fps

this is a .75in load in my rifle with low presure.

I had a couple of 375 H&H ACK IMPs. I used 12" twist barrels. There is no wby freebore. There was one load I used:
300 Sierra
86.5 gr. IMR 4350, no crimp
24" barrel 2810 fps
20" barrel 2680 fps
There could be better loads, but all the guys with them around here tend to use PAC-NOR barrels and that load.

[ 09-10-2003, 06:44: Message edited by: jnrifleworks ]

Yentna River and jnrifleworks,
Two more kindred spirits throwing some more kindling spirits on the fire. Nick will like that, thanks!

I ought to get a .375 Weatherby with no freebore, use a Pac-Nor barrel, and stop wasting powder!

A .375 Weatherby plus a .458 Lott would be a nice pair of pinch hitters to take to Africa.

A toast: Cheers!

350 grain woodliegh PP
84 grains AR2209 2500 fps
Fantastic cartridge!!!

Hey Hector, where can you buy such a diversity of powders in Buenos Aires ???
An "amigo" of mine, just living in your very same city, is begging for components !! (perhaps a could manage to send him some podwer trough my embassy in BA ...) Would probably appreciate your info about this availabilty ....

Using data from the wildcat book of Wolfe's, I loaded up 89 gr of 4350 behind 300 gr Sierras, for 2900 from a 26" barrel. No pressure signs, but it made me a little nervous to get 378 Wby ballistics from it's little brother (there is no free lunch, Heinlein was right), so I dropped back to 88 gr for 2800 fps and change. - Dan

Nickudu, DaggaRom and others!
Thank you for all the reloads and your experience with the Weatherby(in special for the freebore principle).
Now, my next step is rebareled the barrel to .375 Wby and prove your reloads.
Afrikaander, more than 25 years of reloading and travellers is the way for have plenty of differents powders in Buenos Aires.
For your friend, please ask him to call me to my home at Buenos Aires (5411 - 4765 - 7618) and maybe I could help him for buy powders.
Best Regards for all.

H�ctor

Hector,
You are welcome, and thank you for the reactivation of the .375 Weatherby topic. It is a grand cartridge for a hunting rifle. Hard to beat.

Cheers!

Mr. Roveda,

When rebarreling or rechambering to the .375 Weatherby, be sure your chamber has the proper dimensions. There are two versions that I know of floating around. The one shown in the A-Square manual (which copy I will be sending you) is the correct one.

How am I sure? I have two boxes of original .375 Weatherby (Tiger ready to charge on cover), ammunition. I have compared the cases coming out of my chamber to the originals and they are the same dimensionally.

I have an extra Sako in 375 H&H that I am considering reboring to 375 Ultra; however, the 375 WBY also interests me. Can I simply rechamber to 375 WBY without setting the barrel back? It has open sights and I would like to keep them where they're at as well as the factory markings. Lou

[ 09-14-2003, 20:09: Message edited by: DOCTOR LOU ]

Lou-
Yes, your barrel can be rechambered without having to set it back. The Wby reamer, if it has the normal amount of throat length, will easily clean out all remnants of the H&H chamber!
My own 375Wby uses a custom short throat, more in line with an H&H dimension. I use R19 powder and manage to achieve about 2730fps with 300gr Swifts w/o pressure pains. For other bullets I use less/more of R19 to get the accuracy and reliability I insist on. With my rifle the KISS principle is absolutely useless, it will only deliver optimum accuracy and pressure levels with specific charges, and these vary a great deal from bullet to bullet.
Also, I believe Weatherby altered their original throat dimension when they submitted this cartridge to SAAMI a couple of years ago. The newer version I believe has a shorter freebore.

[ 09-14-2003, 22:56: Message edited by: John S ]

Nitroman,
Thanks for the pointer on the A-Square manual. I forgot about that list of reloading data. I will look for a reamer to duplicate that chamber. It doesn't say anything about the throating due to the drawing being of cartridge case specs. I like the way they show the shoulder as a 31 degree angle instead of a double radius venturi. A venturi is kind of ridiculous with a shoulder step that small.

John S,
I hear you and am chastised, again.

Looking at the A-Square data, it would seem that IMR 4831 and RL-19 are the best powders for their chamber and throating.

I did note that 89.0 grains of IMR 4350 gave them 2709 fps and redlined the pressure at 60,100 CUP, with the 300 grain Dead Tough soft point.

With the same bullet, 92.0 grains of RL-19 gave 55,100 CUP and 2743 fps.

With the same 300 grain Dead Tough soft point, 88.0 grains of IMR 4831 gave 2730 fps and 54,400 CUP, with a smaller SD of velocity (10 fps) than any other high velocity load ....

IN THEIR RIFLE WITH THEIR CHAMBER AND WHATEVER THROAT THEY HAD.

Thanks, John. Would there be any advantage/or disadvantage to go with a 375 H&H improved reamer v. the Weathery since the improved reamer probably has the standard throat? Is there any difference in performance between the two cartridges? Lou

[ 09-15-2003, 01:22: Message edited by: DOCTOR LOU ]

Ron-
Chambers for these type cartridges vary a great deal, as I'm sure you know. If your rifle will give satisfactory levels of accuracy and velocity with one load across the board, you are indeed a lucky guy and I'm envious! Mine just will not do so at all...if I want a Woodleigh solid to print decent sized groups to about the same POI as the Swifts there is a significant difference in the charge weight of R19. Also, with identical charge weights the solid goes 100fps faster than the Swift, and I don't need or want 2800+fps for that load.

Lou-
Now that Weatherby has made an honest woman of the old girl and there is factory brass available I see no reason whatsoever to use the Ackley version, which offers no increase in performance. Fireforming is expensive and a pain in the ass, IMO so using the Weatherby is a no brainer. Plus, the case length on the 375Wby is 2.860" max, and fireforming H&H brass will not yield brass anywhere near that length. Firing short brass repeatedly is a great way to erode the neck end of your chamber. My gunsmith removed the throat section of his reamer and does that job in a separate operation. By doing so we were able to lengthen it as needed until we achieved the accuracy and velocity we were after. Even with a factory spec'd throat dimension I'd pick the Weatherby version.

[ 09-15-2003, 04:01: Message edited by: John S ]

John, thanks for the note. I will definitely go with the Weatherby over the Ultra and the improved. Lou

John,
My KISS-and-tell about my "talented" old rifle comes from 1986 notes in my log book, when I was young and foolish.

That rifle would handle the hotstuff, but it would only do 1.5 MOA on a good day with the Sierra bullets, worse with the other bullets. Not the fault of the bullets, just my rifle and KISS loading techniques. It was my first adventure in "custom re-chambered rifles," and a hurryup load development before going hunting with it on Kodiak Island. No excuse, Sir!

I have come to see the light, and need to give the .375 Weatherby another chance with the new Weatherby brass, by Norma, saving the slightly shorter Winchester fireformed stuff for the original rifle, though hopefully its neck has not been roughened too badly.

I think that I may be finally cured of experimenting with wildcats and bigbores!

Forget the .375 Lapua that I was thinking about!

I started with the .375 Weatherby in 1986, and have come full circle back to the .375 Weatherby in 2003.

It only took about 17 years to get this worked out.

I will only have to refine my technique by tailoring the powder charge to the particular 300 grain bullet.

Then I will use the KISS principal with the .375 Weatherby, as Saeed does with the .375/404: One bullet weight for all game large and small, near or far. Plus, you can still make the ubiquitous .375 H&H fodder go bang with reasonable power and accuracy in a pinch.

And no doubt I will get better accuracy with the Norma-Weatherby brass in the shorter freebored chamber.

This will make a new rifle in .375 Weatherby much more appealing than my old clunker ... I am thinking rechamber the M70 Classic Stainless in .375 H&H that is a 3/4 MOA shooter with 300 grain Swifts and Noslers.

Halleluja! I am cured!

Almost! Just two questions:

1) Anybody know the best source for a reamer to match the current Weatherby factory chamber and throat specs? I want my local smith to do it.

2) And just what is the current freebore on their .375 Weatherby?

(IIRC, the old ones, like my Whitworth Mark X, had about 0.700" freebore.)

Ron,
The "new" throat length is .375" I believe. Been a while since I had this project in front of me and did all the fact finding. I know that my rifle uses a throat dimension nearly like the H&H, which is likely a lot differently shaped than a regular "freebore" design. Whatever the case, it works and delivers what I was after...sub MOA groups with velocities of 2700+fps and reasonable pressures, all from a 24" barrel. I still have to juggle loads to get the solids hitting with the Swifts but every bolt rifle I own has required that!
The new Weatherby brass measures about 2.853" out of the box and my initial batch has numerous firings with fairly stiff loads...still not a single loose primer pocket and only a few have grown to the 2.860" max length.
A very nice cartridge overall and one that I enjoy working and hunting with.

[ 09-15-2003, 07:24: Message edited by: John S ]

DOCTOR LOU

I think the 375 Ultra will be difficult to fit into your Sako. I have a 375 Ultra and like it but at full throttle it's not for everyone. You should be sure before you commit to it.

The 375 Wby is a great choice. My friend and I have matching 375 Wby,s. His feeds well and required no mag. work. Mine required a couple of hours of tuning. Both shoot very well.

Good luck!

Jamie

X-Man, I appreciate your input. After kicking it around and taking input from everybody, I will go with the Weatherby. I don't think the old H&H needs any help, I am just looking for something to do. Also, if I want to get beat up, I will use my 416 or rebarrel it to a 458 Lott.
Thanks, Lou