Depending on the age... it might be a 1-66 Douglas barrel. Or it is a 1-48 twist. That's a nice looking rifle there Chap. Heck of a deal. As for changing it over, I guess you would have to contact CVA and see what kind of deal they can make you on a lock...

Personally, I would leave them the way they are. That's almost too nice to change around. Looks like a lot of fun to shoot too...