I've got some from the various reloading manuals, but would be interested the loads AR users are using. I've had mine almost a year, and all I've done with it is fireform brass. I guess nows about the time to start reloading it.
Thanks

JMeier

Just work up with some H 4350 or IMR 4350 and a magnum primer.

It really is that simple.

start with 375HH loads.
http://www.hodgdon.com/data/rifle/375hhmag.php

is a good place to start.

jeffe

HI JMeier,
I've had really good performance and grouping with RL15 and the 270 TSX"s. I worked up to 83 grains for a velocity of 2890 fps. This load is from a 26 inch barrel and groups in the 3/8 to 3/4 group size. You will love your 375 Weatherby.
Take good care,
Dave

Here is some very extensive testing from member RIP. This is posted up om the loading section of Saaed's site
www.accuratereloading.com

http://www.accuratereloading.com/375wby.html

Mike,
That is a blast from the past!

Subsequent to that data I found that H4350 Extreme is better than the IMR 4350, with 300 grain bullets in the .375 Weatherby.

Using Norma made .375 Weatherby headstamped brass (greater capacity than my Hornady basic hulls) and seating the bullets out to 3.75" in a CZ 550 Magnum box, with the 2001 .375 Weatherby throat, GM215M primer, H4350 Extreme:

88.0 grains gave about 2825 fps in a 25" CZ barrel, with no pressure signs ... I would have to check my notes to see exactly which 300 grain bullets those were ... work up from 10% less.

Thanks to all

470MBOGO, RE 15 and 270gr Tsx's are what I use in my 375H&H, and that is what I thought I'd use in the wby. Mine has a 26" bbl also. Depending on how ambitious I get, I'll post results in a few weeks.
Thanks

JMeier

I have yet to venture beyond 250 gr. Sierras so far. I'm just getting started. A few things I have found with the light bullets in my rifle:

...IMR-4320 sucks

...The various 4350's are all good.

...H-414 is superb

...a Fed 210M gave me better groups & velocities than the 215's

...The Sierra 250 grainer will drive a looooong way through a big game animal (waaay farther than I ever imagined).

...The old Weatherby headstamped brass has less case capacity than the new stuff. Work up slowly in either instance.

...The .375 Weatherby is one heck of a fun round to load for and shoot!!

here's a few 300 grain loads from Hodgdon
300 Swift SP Hodgdon H-4831 93.0 2,649 3.560"; 54,200 cup
300 Swift SP Hodgdon H-4350 85.0 2,642 53,500 cup
300 Swift SP Hodgdon H-414 84.0 2,623 52,700 cup
300 Swift SP Hodgdon H-380 75.0 2,458

quote:

Originally posted by vapodog:
here's a few 300 grain loads from Hodgdon
300 Swift SP Hodgdon H-4831 93.0 2,649 3.560"; 54,200 cup
300 Swift SP Hodgdon H-4350 85.0 2,642 53,500 cup
300 Swift SP Hodgdon H-414 84.0 2,623 52,700 cup
300 Swift SP Hodgdon H-380 75.0 2,458

Note those are CUP so the PSI's are in the over 60K range. They are max loads.

That means the Hodgdon folks have a slow test barrel, and/or the Swift bullets with the thick partition, full diameter, and large bearing surface, do jack pressures up over what can be done with some other bullets that will give higher speeds at lower pressure.

quote:

Originally posted by RIP:

quote:

Originally posted by vapodog:
here's a few 300 grain loads from Hodgdon
300 Swift SP Hodgdon H-4831 93.0 2,649 3.560"; 54,200 cup
300 Swift SP Hodgdon H-4350 85.0 2,642 53,500 cup
300 Swift SP Hodgdon H-414 84.0 2,623 52,700 cup
300 Swift SP Hodgdon H-380 75.0 2,458

Note those are CUP so the PSI's are in the over 60K range. They are max loads.

That means the Hodgdon folks have a slow test barrel, and/or the Swift bullets with the thick partition, full diameter, and large bearing surface, do jack pressures up over what can be done with some other bullets that will give higher speeds at lower pressure.

yes....those are MAX loads from Hodgdon.....

FWIW all the loading data I've ever seen for the 375 weatherby published by people using pressure barrel data have show it about 100-150'/sec better than the H&H.....not what some might believe as there are those that put it in the .378 Weatherby class and it's not at all there.

And some people like to say that 2600 fps is standard with the .375 H&H and 300 grainers, and the Hornady and Federal voodoo loads give 2700 fps with the .375 H&H and 300 grainers (which are erratic and deliver 100 fps less than claimed in my 24" barrels, with poor accuracy).

The sloppy old freebore from the 1940's may be what Vapodog disparages. The 2001 chamber specs brought the .375 Weatherby back to clearly superior. I would not be surprised if the Hodgdon data is not the same old tired data they have been posting for many years before 2001.

I have worked with six different .375 H&H rifles, one old-throated .375 Weatherby and two new-throated ones, over the last 21 years.

Here is how they rank with same bullets, 300 grainers, in 24" barrels, and limited to 3.600" COL:

.375 H&H: 2550 fps
.375 Wby: 2750 fps: way better than a voodoo load

I consider that worthwhile.

With 350 grainers the Wby has even greater velocity advantage over the H&H: 250 to 300 fps, with bigger quantities of slower powders keeping pressures under max.

With lighter bullets like 235 to 270 grainers, it is in the 100 to 150 fps advantage range for the .375 Wby: just can't handle much higher charges of the faster powder before exceeding max pressures with the lighter bullets, requiring faster powders.

When you fire standard H&H loads in the Wby chamber, you only lose about 100 to 150 fps, and turn the 300 grain H&H factory load into a slowed down, 2400 fps, super killer with lighter recoil, and good accuracy within 3" vertical drop from POI at 100 yards, as compared to the Wby zero.

The .375 Wby gets same velocity with 300-grain bullets as the .375 H&H gets with 270-grain bullets.

The .375 Wby gets higher velocity with the 350-grain bullets than the .375 H&H can do with 300-grain bullets.

Remember those Remington factory loads with the 300 grain Swift A-Frame .375 H&H? They would blow primers and extract hard, and give extrusion marks on the case head, at only "2530 fps," ... I am not the only one to post that observation here, others have seen it too.

RIP

John S and myself have both agreed we need to get Chronys

Much less recoil for the same velocity ......But it can depend on the light conditions

Mike

quote:

Originally posted by Mike McGuire:
RIP

John S and myself have both agreed we need to get Chronys

Much less recoil for the same velocity ......But it can depend on the light conditions

Mike

Mike,
You are going to have to help me understand that joke.

I know John S has done extensive chronographing already with his D'Arcy Echols rifle in .375 Weatherby, and I know John S has a very short custom throat and he better be careful with firing the .375 Weatherby factory ammo in his rifle.

The factory ammo did an actual 2740 fps with Nosler Partition 300 grainers in my 24" barreled 2001 throat. Oehler certified.

That squares well with Weatherby's claim of 2800 fps in the 26" barrel.

Those cartridges are loaded with 88 grains of some Swedish powder by Norma, and the powder still rattles when you shake the cartridge beside your ear. It is about a 95% load density.

Ron,

Known as the velocity reducing Oehler


Mike

Oh. I get it now.

quote:

Remember those Remington factory loads with the 300 grain Swift A-Frame .375 H&H? They would blow primers and extract hard, and give extractor marks on the case head, at only "2530 fps," ... I am not the only one to post that observation here, others have seen it too.

You may recall that one of them even blew a primer in my 375H&H. Broke the extractor too, so I had to knock the case out with a cleaning rod.

Canuck

Thank you Canuck. I recall it well. I had pierced primers and brass extrusion signs and sticky extraction with the same ammo. Luckily my rifle got off easier than yours did. That .375 H&H was rebarreled to .470 Capstick, for some arbitrary reason.

I do believe those Swifts give higher pressures for a given velocity, or lower velocities when loaded to max pressure than most other bullets. They are tough/hard/accurate, but gotta be loaded appropriately.