I am intrigued with the rebore of lever 30-30 to things like 356 win and 375 win etc. etc. I wonder if this is safe? 30-30 operate with an average max pressure of 38,000 cup. 356win and 375win operate with an average max pressure of 52,000 cup. I wonder is this safe or a pending disaster?

Depends on the gun. Personally, I would utilize a post-1914 Savage 99 action. Using a .30-30/.303 rotor will give you your best chance at feeding ok- I can visualize the .375 feeding swell, but not so sure about a .356 without altering the "cartridge saddles" on the rotor.

Why not just re-bore to .35-30 wildcat? Performance on par with .35 Remington = plenty of moxie for anything that you're likely to encounter in the Lower 48.

That depends on the action you are wanting to use.
The 356 and 375 Win were both made for lever actions.
The marlin 336 action is quite strong. The m94 Winchester is less so, and depending on when it was made it can be a lot less so. However the 375 Big bore was a modified M94 with beefed up sides to give extra strength, so again it all depends on the specific action used.

The 35/30 rebore was a popular rebore. Especially for the pitted bores of the 32 win special 1894's

And remember also that even though a given action may be "strong" enough, said gun is likely to be used with hot handloads, given the knuckleheaded predilection for that in this day and age. At that point the marginally ok action becomes not so good a choice. Unless the Marlin is of the series that the factory utilized for the .356, and the 94 is one of the Big Bore actions, I would think long and hard about such a conversion. Again, the Savage 99 comes to mind as best. (And I guess the BLR and probably some others, but I have never looked twice at them so can't speak to their utility.)

I have had Marlin 336s rechambered from 30-30 to 307 and from 35 to 356 without an concerns.

JES advertises that they rebore Marlin 336s to 356.

www.35caliber.com

JES advertises that they rebore/rechamber Winchester 94s from 30-30 and 32 WS to 38-55 and 375 Win.

I had JES rebore a pre 64 Winchester 94, to 38-55

Worked GREAT and accuracy was GREAT.

The action worked great with no changes.

Virgil B.

I wonder if the Win 94 in 30-30 could be bored to 35 Rem?

JES did my 336 in 30-30 to 356. I wanted to shoot heavy cast bullets and had to have some work done to feed 280gr cast bullets. Nonemann (guy who made it feed) said I could swap out parts to a 45-70 also, but I sent the parts to him for machining.

No issues with the 356 - I don't try to get every bit of horsepower out of it though.