I have an Interarms Mk. X (Whitworth marked) action (only), unused, still in original box. .458 Win Mags will fit (easily) in the magazine and will fit the bolt face and will extract. My question is: How do I determine if this action is long enough to take the .458 lott? .416 Rigby will fit in the magazine but its obvious they are to long to extract loaded (also hard to feed out of the magazine box). Is there an easy way to determine if my action is large enough for the .458 lott?

Funds are somewhat limited and I'm really just looking for something big bore to shoot. I have the action and I have a nice piece of walnut to put it in.

Thanks,

jlbell