Considering joining the club...

[old tanker]

So...with all that, a better choice for the sub cal chambering would be either .460 S&W or even .500 S&W to engage the rifling. They would still have lots of power and still be tame for that rifle. The problem however is wanting to shoot lead bullets and the OP doesn't want to reload his ammo...no factory lead loads are available that I'm aware of, although there are companies that do custom loading in the US aplenty... I would do it for him if I was even in the same country. Having a sub cal made and chambered would still be cheaper in the long run that laying out for dies, brass, bullet molds...or buying from someone that custom loads 577/450...

This gets more complex...

There was some discussion about an adapter using the .480 Ruger cartridge over on the British Militaria Forum. Dimensionally it would be an almost ideal fit, but no commercial sources. But finding lead bullet .480 Ruger is about as easy as .460 S&W. So it's back to handloading ammo, plus being good enough with a lathe to make yourself an adapter you can't just buy.

(As an aside, some people use .480 Ruger dies to neck size 577-450)

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