Is it possible to rebarrel a 7MM mag Mark X Mauser to 416 Remington? If so would the mag box have to be lengthened? Or do I need to start with a 375 action?

thanks

You can do it with the 7mm. You will have to open the action up fore and aft. You will also have to extend the mag box. If you can find one in 375 it will be done already.

This is a major conversion...can be done...bring $$$$

Yep it has been done. The MKX 375 has most of the space gained in the front. Meaning removal of a larger amount of the feed ramp and metal behind the bottom locking lug.

A 416 Taylor or 416 Ruger would give up very little to the 416 Rem and take far less work.

the 416 AR will fit in that length action, the 416rem is .300 and will cost cubic dollars to do right...

Thanks for the input. No use spending $$$ to prove a point!!