Does anyone know what the largest cartridge is that you can chamber in a ruger 1? I'd like to know if its possible to get a 50 bmg fitted to one. But I dont own one or have dimensions. Any help...

I don't think a .50BMG would work, it's 5.45 oal, pressure and recoil make it tough. Maybe a .50 Beowulf.

I think not. The action is not large enough. I would not care to shoot one if it will? I don't think most bolt rifles are big enough either? Single shot or not.
I do think the type of action is strong enough. And then some. Won't fit is the trouble.

Cheezywan

Think SSK was advertising .577 Nitro Express and the like in #1s a while back. Not sure what they are currently offering.

I'd suspect that will be all the recoil you need, and then some.

The OAL has nothing to do with it in a falling block action. The problem is the barrel shank may not be large enough to accommodate this big old fat cartridge. I don't think it will handle the 50 bmg but why not Email Ruger and ask them.