Home Forums Hunting & Shooting Express Rifles and Big Bores Only Anyone 375 Roy?

Ooh ! Mighty thinskinned about the M700, eh ?
I am too !
Whatever you do, use the latest C.I.P. homologation of the .375 Weatherby Magnum, circa 2001 Weatherby redesign, revised in CIP circa 2002, IIRC.
Don't get the old 1945 version reamer.

My first in 1987 Alaska, also was my first "semi-custom" rifle and the next-to-fugliest one I still own.
It was the first rifle I ever had a gunsmith build for me, and he was allergic to epoxy, so this is the first rifle stock I ever bedded and finished exteriorly.
It is a Brown Precision, believe it or not, smeared with epoxy and sprayed with Krylon.



Nirvana occurred after 2001:





Above was a 300-gr bullet loaded longer than 3.600" COL because of the weird bullet anatomy,
and it used uncharacteristically fast powder for the unusual bullet.
Generally, H4350 with 300-grainers is the way to go with the .375 WBY.

The only weakness of the .375 WBY is lack of magazine space for long-nosed bullets to work through the magazine,
unless you get a 3.8" magazine or a single shot rifle:



Though I have full-custom .375/.338 Lapua Magnum (9.5x70mm Tornado) and .375/.404 Jeffery rifles,
I had them built with custom reamers utilizing the .375 Weatherby Magnum throat of CIP 2002,
both with fluted, stainless Lilja No. 6 sporter contours, 26" long.
One is as good as another among all three chamberings, no significant difference.
24" barrel will be about 50 to 60 fps slower than 26" barrel,
Expect 300-grainer MV of 2740 fps to 2800 fps for .375 WBY, with 24" to 26" barrel.
Simply re-chambering a .375 H&H to .375 WBY is very worthwhile, and a cost-effective way to get a .375 WBY.
Remember, use the correct reamer.

A funny thing about the Mark V DGR Weatherby makes, even with the drop floor plate, they manage to limit it to only 3 down in .375 WBY,
yet they use a flat follower and get 3 down with the .378, .416, and .460 WBY.
I have one in .416 WBY, would have gotten it in .375 WBY except for the silly drop floorplate that allows only 3 down in the DGR.

I must confess that I do have a Remington M700LSS .375 RUM factory rifle hiding in the safe.
It has a slender 26" slick barrel.
On 11-18-2001 at 70*F in KY, I chronographed 20 rounds of Remington factory 300-gr Swift A-Frame ammo.
5-yard chrono readings:
Ave = 2780 fps
ES = 80 fps
St. dev. = 24 fps,
Correction to MV = 2794 fps.

The best 3-shot group during that session at 100-yard targets was 0.52 MOA.
Sometimes I get lucky and get 3 factory rounds in a row close to same velocity.

An acquaintance told me the factory load for the .375 RUM with 300-gr Swift AF can be duplicated with
93.0 grains of IMR-7828 and the Remington 9-1/2M primer in Remington brass.
And you can improve the uniformity of velocities with handloading.

By golly !
The .375 RUM performs almost as well as the .375 WBY.
But the .375 RUM burns more of a slower powder in a bigger case capacity with a shorter throat.
The .375 RUM is to the .375 WBY as the .458 Lott is to the .458 WinMag, when all are used in the same length actions.

Another neat thing about the .375 WBY is that it will totally clean up a .375 H&H chamber without setting back the barrel.
Try that with a .375 RUM reamer in a .375 H&H chamber and you will get a deformed/compound shoulder on your .375 RUM chamber.
You have to set the .375 H&H barrel back to re-chamber to .375 RUM.

Sure the Remington M700 is acccurate and a strong action,
But one bad experience of having its extractor shaving brass filings that clog up that tiny little plunger ejector can make a lasting impression.
I save my Rem M700 .375 RUM for show and tell purposes,
just like the 7mm STW and the .300 WBY M700's I purchased before I knew any better.
That is all I allow to keep themselves company in the safe.
They are accurate and strong and light weight, but they make me nervous with their extractors and ejectors and controversy over the safeties,
the latter issue never being an issue for me.
Knock wood.

Oh nice talk... I’ll letcha flap your lips about controlled feed bullshiit while I do my thang with push feed.... while laying on my back, pretending things went “bad”.... haha

The dumbat their finest!! 👍👍👍

Buff meets 416 Rem at 130 yards. Boom, stumble two steps, boom falls over. Little 350 gr TSX.

EdM,

Nice buffalo.
I sure hope that is a Wisner copy of the "African" Winchester rear sight
on a fine custom rifle,
and not one of those pot metal Remington rear sights.
Kind of hard to see.
Please show and tell more about that rifle.

350-gr TSX from a .416 RemMag, eh? How fast was that bullet going when it left the rifle ?

For comparison, keeping it .375 WBY related, I have a handload for the Barnes Original 350-grainer, and a few more tidbits.

Brass: .375 WBY formed from Hornady basic cylindrical H&H brass, trimmed to 2.850", and necks annealed.
Primer: Federal GM215M or F215 (same/same)
Powder: Norma MRP 90.0 grains
Temperature 50 degrees F
Bullet: 350-gr Barnes Original, BC = 0.370, SD = 0.356
5-yard velocity = 2563 fps
MV = 2575 fps
KE = 5153 ft-lbs
Accuracy: Just under 1.5 MOA for 3 shots at 100 yards, 24"-barreled Winchester M70 Classic Stainless rechambered from .375 H&H,

Same rifle, powder and other load specifics/conditions as above except with 300-grainer and 2 gr more powder:
92.0 gr Norma MRP
Bullet: 300-gr Sierra GameKing, BC = 0.458, SD = 0.305
5-yard velocity = 2742 fps
MV = 2752 fps
KE = 5045 ft-lbs
Accuracy: Just under 1.0 MOA for 3 shots at 100 yards.

Same day, same rifle, .375 Weatherby Magnum factory ammo, with COL = 3.565", containing 88.5 grains of unknown powder (N-204?):
Bullet : 300-gr Nosler Partition, BC = 0.398, SD = 0,305
5-yard velocity = 2734 fps
MV = 2745 fps
KE = 5019 ft-lbs
Accuracy: 1.0 MOA for 3 shots at 100 yards.

The Weatherby factory ammo claim of 2800 fps with 300-grainer in a 26" barrel is spot-on, compared to my 24" barrel.

Also of note:
The properly headstamped, Norma-made .375 WBY brass has a greater water capacity than brass made from W-W .375 H&H or Hornady basic.
111.5 grains H2O for Norma brass at 2.860" maximum length.
108.4 grains H2O for fire-formed W-W .375 H&H that comes out short at 2.832" after fire-forming.
108.2 grains H2O for the Hornady basic brass at trim-to-length of 2.850".

I later discovered that H4350 in the Norma brass with any 300-grain bullet preferred is the way to go for one bullet weight does all in the .375 Weatherby,
with better accuracy and top velocity.
I also discovered that the make of bullet used has a lot to do with accuracy of the rifle. Duh.

Never heard of Leroy or Jim, though I remember their shop from, oh, 1982 or thereabouts... grin

Some great performance from lighter bullets in the H&H... If heavies interest you, the BEE is the better design. I have necked down the WBY.375 case to 9.3 MM . (Now that there ,is something that needs looking into. I call it a 360 WBY.) I feel the 350 Barnes RN was the reason the BEE came into it's very small window of popularity. There were no reasonable 40 caliber rifles back then. A 350 at 300 speed seemed a bit better Buff cartridge. Remember all it took was an oil man or a banker and a gun writer to sell a few magazines and make Joe Lunchbox wish he could go to Africa. Herter had a book about going to Africa for $630 !

Riflecrank,
What velocities were you getting with the 375 WBY and the 270 & 300 grain Barnes TSX ?
The 375 WBY is an intriguing cartridge.

I bought a used Remington custom shop rifle that was advertised as a 375 H&H but was a bit surprised when the cases of the first loads I tried came out with the Weatherby shoulder. I thought about returning it but it is so accurate I had to keep it.

Lol 😂. I bet looking at that fired brass the first time was a heck of a surprise!!

My early Sako FN 98 in 375 Wby. This is one of my favorite rifles. The basket weave is meticulously done hand carved. Has one standing/one folding. The Timney trigger is light and crisp. It is presently wearing a Loopy 2.5-8, not the Burris 3.5-10 in the photo.

Great rifle and cartridge. Thanks for sharing the pictures.

My 375 H&H AI will shoot the 375 Weatherby in it, but it's almost the same ballistics. Main difference is the shoulder. I like it and it is a pleasure to shoot - not hard recoiling.

I have had a 375 Wby as well as two 375 Improved 40 degree rifles. I got increased velocities but also got recoil more like a 416 rather than the 375 H&H. I sold all three. I would rather have more bore and bullet weight if I am going to get that level of pounding. The RUM is even more “excitement”.

Incidentally if your M700 is accumulating brass shaving which clog the ejector then you may want to back your loads down and eliminate the brass extrusion.

ldmay375,
Sorry, but the TSX did not exist when I settled on the 300-gr Nosler in the .375 Wby to match the factory ammo.
I later shot TSX bullets in the .375/.338 Lapua and .375/404 Jeffery.
Fine bullets, the TSX and TTSX. You will not go wrong there.

True. I was using Remington factory .375 H&H ammo when that happened to me.
It just ruined me on Remington, at a young and impressionable age.

Good for jackrabbits though. I had one and never even fired it. Bought it for $600.00. Sold it on GB for $1,600.00. Didn't even last 2 days there:



I don't get the, lets build a custom for $2,000.00+ idea, when there are so many damn good used rifles out there that can be had for excellent deals.. Often times these "big bores" never even get fired, so when you find one they are generally great shooters. The pre 64 375H&H I did have and later sold to gunner is a "one holer"...

I would never run a 700. Model 70 is where its at, or even a Whitworth or commercial Mauser, but not a 700. Akin to running a Leupold rifle scope...

bsa1917hunter,
You were plumb righteous until you badmouthed Leupold.
Nothing wrong with a Leupold 2.5X20mm Ultralight or 2.5-8X36mm.
I'll take one each of those for any rifle known to man.

You've been lucky then, I've had enough Leopold problems that I eliminated them on my rifles.