Humm what to build... Not a Weatherby Rifle but maybe a Weatherby Caliber ..

[HuskyMusky]

338 Edge, ie. (338-300 RUM) google it...

I think the .340wby is probably the ideal balance of everything in the .338 cal though.

[BB340]

I am in a similar position... I have a CZ 602 currently in .375 H&H. So I was trying to decide to go .375 RUM, 404 or if possible open it up and do a .505 Gibbs, 500 Jeffery or the 500 A-Square....
I think I will just settle on the little one of the lot and do a long throated .375 RUM as I have a heap of brass and dies for it.

[Baws]

I am in a similar position... I have a CZ 602 currently in .375 H&H. So I was trying to decide to go .375 RUM, 404 or if possible open it up and do a .505 Gibbs, 500 Jeffery or the 500 A-Square....
I think I will just settle on the little one of the lot and do a long throated .375 RUM as I have a heap of brass and dies for it.

Yes, I am leaning toward the .375 RUM as I have plenty of 340 Weatherby Magnums, 300 RUM, 338 RUMs, 338 Edge, 338-378 and 338 Excalber.   375 Projectiles in a single shooter especially have evolved with very high BCs!

[Baws]

338 Edge, ie. (338-300 RUM) google it...

I think the .340wby is probably the ideal balance of everything in the .338 cal though.

I have many rifles chambered in the 338 RUM.  I did the 338-300 before it came out.   The 340 is very efficient "as-is" and in a single shooter can be pushed to nearly match the 338 Lapua Magnum in velocities easily.    The only reason I would move to the .375 calibers is that most of my close up big bear encounters would make me feel better with a 270 or heavier bullet in the .375 caliber vs. the 340 Weatherby Magnum.   That is the only reason I would not choose a 340 Weatherby Magnum again but all of my 340s have nailed bear easily dispatched as it had with Moose as well.   Something about the psychological feeling of going up to a bear with a 375 caliber however especially since I have basically 1 shot and no matter what most say, the Ruger N01 in a "bad situation" is no where as fast chambering a bolt gun... ask me sometime how I know that!   I literally shit my pants on that hunt ...  LOL

[HighDesertHunter]

338 Edge, ie. (338-300 RUM) google it...

I think the .340wby is probably the ideal balance of everything in the .338 cal though.

I have many rifles chambered in the 338 RUM.  I did the 338-300 before it came out.   The 340 is very efficient "as-is" and in a single shooter can be pushed to nearly match the 338 Lapua Magnum in velocities easily.    The only reason I would move to the .375 calibers is that most of my close up big bear encounters would make me feel better with a 270 or heavier bullet in the .375 caliber vs. the 340 Weatherby Magnum.   That is the only reason I would not choose a 340 Weatherby Magnum again but all of my 340s have nailed bear easily dispatched as it had with Moose as well.   Something about the psychological feeling of going up to a bear with a 375 caliber however especially since I have basically 1 shot and no matter what most say, the Ruger N01 in a "bad situation" is no where as fast chambering a bolt gun... ask me sometime how I know that!   I literally shit my pants on that hunt ...  LOL

Had a similar experience with my T/C Encore Pro Hunter with the .500 barrel on it. My intent was to take out a front leg hoping to catch a lung too. I did but I swear it was faster on three legs than 4. The second shot took off most of it's lower jaw and he dropped just about 10 feet from me. Oh it's just a black bear they said.. Never again with a single shot rifle and a hunting partner that can out run me.

[Baws]

338 Edge, ie. (338-300 RUM) google it...

I think the .340wby is probably the ideal balance of everything in the .338 cal though.

I have many rifles chambered in the 338 RUM.  I did the 338-300 before it came out.   The 340 is very efficient "as-is" and in a single shooter can be pushed to nearly match the 338 Lapua Magnum in velocities easily.    The only reason I would move to the .375 calibers is that most of my close up big bear encounters would make me feel better with a 270 or heavier bullet in the .375 caliber vs. the 340 Weatherby Magnum.   That is the only reason I would not choose a 340 Weatherby Magnum again but all of my 340s have nailed bear easily dispatched as it had with Moose as well.   Something about the psychological feeling of going up to a bear with a 375 caliber however especially since I have basically 1 shot and no matter what most say, the Ruger N01 in a "bad situation" is no where as fast chambering a bolt gun... ask me sometime how I know that!   I literally shit my pants on that hunt ...  LOL

Had a similar experience with my T/C Encore Pro Hunter with the .500 barrel on it. My intent was to take out a front leg hoping to catch a lung too. I did but I swear it was faster on three legs than 4. The second shot took off most of it's lower jaw and he dropped just about 10 feet from me. Oh it's just a black bear they said.. Never again with a single shot rifle and a hunting partner that can out run me.

LOL now that is funny (NOT), yeah then you too know the crap the pants experience.... however the 375 RUM or 378 WBY Mag in a single shooter will be significantly more powerful than a .500 S&W even at point blank range, so there is stilll some element of risk there, the pure advantage of put-down energy should make the difference.   I know I posted this before but this is my "little" side-arm that always goes with me when in BIG Bear Country despite the rifle I may have... it too a single-shooter TC Encore but it is the equivelent of 3 500 S&W pistols in a single shot...

458 Lott Pistol -- very few things walk from this weapon of any size....

https://photos.app.goo.gl/JySNgLQgyTSvBBni8

[HighDesertHunter]

338 Edge, ie. (338-300 RUM) google it...

I think the .340wby is probably the ideal balance of everything in the .338 cal though.

I have many rifles chambered in the 338 RUM.  I did the 338-300 before it came out.   The 340 is very efficient "as-is" and in a single shooter can be pushed to nearly match the 338 Lapua Magnum in velocities easily.    The only reason I would move to the .375 calibers is that most of my close up big bear encounters would make me feel better with a 270 or heavier bullet in the .375 caliber vs. the 340 Weatherby Magnum.   That is the only reason I would not choose a 340 Weatherby Magnum again but all of my 340s have nailed bear easily dispatched as it had with Moose as well.   Something about the psychological feeling of going up to a bear with a 375 caliber however especially since I have basically 1 shot and no matter what most say, the Ruger N01 in a "bad situation" is no where as fast chambering a bolt gun... ask me sometime how I know that!   I literally shit my pants on that hunt ...  LOL

Had a similar experience with my T/C Encore Pro Hunter with the .500 barrel on it. My intent was to take out a front leg hoping to catch a lung too. I did but I swear it was faster on three legs than 4. The second shot took off most of it's lower jaw and he dropped just about 10 feet from me. Oh it's just a black bear they said.. Never again with a single shot rifle and a hunting partner that can out run me.

LOL now that is funny (NOT), yeah then you too know the crap the pants experience.... however the 375 RUM or 378 WBY Mag in a single shooter will be significantly more powerful than a .500 S&W even at point blank range, so there is stilll some element of risk there, the pure advantage of put-down energy should make the difference.   I know I posted this before but this is my "little" side-arm that always goes with me when in BIG Bear Country despite the rifle I may have... it too a single-shooter TC Encore but it is the equivelent of 3 500 S&W pistols in a single shot...

458 Lott Pistol -- very few things walk from this weapon of any size....

https://photos.app.goo.gl/JySNgLQgyTSvBBni8

My T/C came with a Contender but I bought it used and the Contender had already been sold. I have the 7mm Rem Mag barrel and a .308 barrel for it also. Considering the price, it's a pretty good little rifle. I believe I now own a much better bear rifle. It's a little on the heavy side for hunting but I'm pretty sure my Barrett M82A1 will get the job done. LOL

[HuskyMusky]

My 375 and 416 choices are the, 375 H&H and 416 Rigby.

I personally would not want a 378 with a brake...

375wby looks pretty nice, if one wanted more than the H&H. There's also the Ruger, I always thought an Ruger version that was as long as the H&H would be pretty perfect...

[TXWBY338]

The 338-378 is an impressive caliber and plenty of bullet options in a wide weight range. The 378 is a beast as well. I have hunted elk with the 338-378 and it is serious medicine for them.

[Northern hunter]

One of the Chey tac calibers or for shits and giggles a 14.5 ,x 114mm.

[Chris338378]

Based on what you said you have and plan to do with the rifle I would make a .375 Weatherby magnum.  One advantage to this caliber is you can shoot .375 H&H Magnum ammo out of it without any issued and it'll fire form the brass into the .375 Weatherby Magnum. 

For my next rifle I'm going to get a Sako action and build a .358 Shooting Times Alaskan.