Ah well I’d still own one
Re .378 WbyMag:
Had to find out what all the whining was about.
My first was a BRNO ZKK 602 .375 H&H that someone had cut down to 22" length, so I had it re-chambered to .378 WbyMag.
That was in 1998.
Factory Weatherby brand 300-gr FMJ RN (yellow box with tiger logo)
shot about 3-MOA for 3 shots and bolt lift was sticky, primers cratered, ejector mark/smear on brass.
I fired three more shots, no better, and 6-shot average at 5 yards was 2851 fps.
MV corrected = 2868 fps.
I figured 4" of shortening must have indeed lowered velocity about 120 fps, versus the claimed 3000 fps for 26" barrel. About 30 fps per inch.
Recoil was nowhere near the horrible of legend due to slowed velocity, but muzzle blast was.
Eventually I found a most accurate, trouble-free load with 300-gr Swifts and Sierra Game Kings, using 111.0 grains of IMR-7828.
The Sierra GK did 2747 fps, Swift did 2780 fps, 5-yard velocities from the 22" barrel.
Not so great way to make a .378 WbyMag shoot like a .375 WBY MAG, eh ?
A couple of years later I rechambered a CZ 550 Magnum .375 H&H with 25" factory barrel to .378 WbyMag. Pillars, glass bedding, and cross bolts, with CZ barrel recoil lug contraption glass bedded too.
The 111-gr charge of IMR-7828 with 300-gr Swift A-Frame gave 2878 fps at 5-yards so right about 2900 fps for MV, and 3 shots at 100 yards grouped under an inch.
A later lot of factory ammo did 2911 fps with 300-gr RN FMJ and grouped over 2-MOA for 3 shots at 100 yards. No pressure signs. Factory ammo had been tamed down by 2000 A.D.
Yet the factory .375 WBY MAG ammo with 300-gr Nosler bullets did an honest 2800 fps in 26" barrels and just over 2740 fps in my 24" barreled Winchester M70.
About identical to a .375 RUM, which I also have tried in 23" and 26" barrel lengths,
since my .378 WbyMag adventures.
I was young and foolish then.
I concluded that the stories of horrible recoil and poor results from a .378 WbyMag are due to light weight factory rifles that fit the shooter poorly plus excessive factory loads with poor bullets back in the old days.
Somebody had great results with a .375 WBY MAG Mark V DGR:
I would be proud of that rifle too.
PS: I have two factory take-off barrels for .378 WbyMag, both cut to 22" length.
One is for a Wby Mark V, the other is for the BRNO ZKK 602.
I will use them for either tomato stakes or rebar in a planned patio.