I have a custom Mexican 1910 7x57 and Ruger m77v .243 rifle. I have a fixed 4 power Leupold and a Nikon Prostaff 4-12x40.
I have proven the Leupold works very well at 50 yards and looks better on the small mauser action. The the Nikon has never been out of the box.
I need to use what I have and not buy another scope for now. What scope would you mount on what rifle?
Thanks

7x57 gets the 4 power
243 gets the 4x12

Agreed.
The varmint rifle needs the magnification if it is ever uses as a varmint rifle.

The Mexican Mauser is at its best with a small compact scope like the 4X.

For sure...the Mex will look better with a smaller Leupold, and the style of the Leupold spans a long period of time, so it will look more "period-correct". The Nikon looks more modern, and you can use the extra magnification on a 243.