Is a .358 X 50 BMG going to be legal in CAL.? now that the .50 BMG is a thing of the past? or roger

Well, not sure about legality, but considering the 338/50 Talbot was grossly overbore, the 358/50 BMG will likely not fare better. Might I offer three other options? I do not know whether ANY of these will be allowed in CA ...

Option 1 -
458/50 BMG. Far less overbore, close to the original round, should be a go getter. Lots of bullet choices.

Option 2 -
50 Spotter AI. I have already seen one shop offering this and performance in shorter barrels is actually almost same as 50 BMG. Faster powders and with the short fat column should be rather accurate. Can rechamber existing 50BMG barrels.

Option 3 -
500 Jeffery "Deep Throat". Simply use the 500 Jeffery and throat it deeper to allow use of 50 BMG projectiles. Relatively close to the 50 BMG in performance.

Just some ideas ...

Well, can't claim to know, but the ban is on 50 caliber BMG. I'm sure all 50 calibers are on the top of the list, just under 338 Lapua perhaps, of things they'd like to see banned, but the only thing the 358x50 has against it is a bunch of powder. Their claim rests on the supposed threat of these giant military bullets hitting something with 4k ft lb at 2000 yd, or whatever insane ballistics the BMG has.
But beware. As soom as they start to draw up the rationale onto paper, they can find all sorts of reasons the people of Kali only need a 22LR and a 410 shotgun, single shot both.
Good luck out there.

I thought I heard about that chambering and that somebody had made some incredible heavy weight 30 cal bullets that gave the cartridge a down range trajectory like a tomahawk missile.

Red

Just venting,guys roger

I saw a 375/50BMG when I was in North Carolina about 20 yars ago, with handmade 450 grain spitzers it really reached out and touched things.

the way the Ca. ban law works, is that a gun is banned if it can chamber and fire a 50bmg round. It even gives the specs of a 50bmg round down to the .00" So, ... all of the wildcats even those that use .510 projectiles are still legal. (if they cannot be chambered or fired in a 50bmg)
Lots of 50bmg manufacturers are looking into the 50 DTC, they used it in Europe to get past military gun bans

Move out of Kalifornistan. That would be my suggestion.