Hello and welcome to the site!

First off, sorry for the loss of your grandfather.
I hope the rifle somehow keeps him alive with you on your future hunts.

Second, get some images of it up here for us to see and we'll go from there on age/identification/etc

Do you have any of the reloading equipment or ammunition he used with it?
There was more than one cartridge chambering offered for these rifles.

Cheers
Tinker