375 and 416 Rigby as you said you want a big noise maker.

The 416 Rigby, like the big Wbys based on the 378 case has the big gun feel about it and when loaded up will be using heaps more powder than a 458 Lott.

You said on price you can to the Ruger.

Well what about a pair of CZ 416 Rigbys and rebarrel one of the 416 Rigbys to either 338 Lapua or 338/378 Wby or the 378 Wby. You should be able to do that for the price of a pair of Rugers in 375 and 458 Lott and money left over.

In fact you might have enough change left over from getting a pair of CZ 416s as compared to the pair Rugers to allow you to rebarrel one of the CZ 416s into 450 Rigby or 450 Dakota or 460 Wby.

Alternatively, what would easy to do and would be a class act and probably fit your budget of two Rugers is to start with the pair of CZ 416 rigbys and rebarrel them to 375/416 and 450 Rigby.

Dies for 375/416 are easy from Redding as the 375/416 is the same body as the 416 Rigby, that is it is not a 416 Rigby Improved necked to 375.

This would be like classier versions of the 378 and 460 Wby

Guns don't get much bigger or noisier unless you moved onto the 505 Gibbs bases stuff and then you run into brass problems and rifle conversion complexities.

Mike