Good call, but I watched an old , "Ramar" episode or two recently and I think Jon Hall actually had a rifle based on a Mauser action, but with a stutzen style stock. I wish that the film resolution had been better.
I couldn't tell which rifle his pal Howard had, but both seem to have worn Colt OP .38's with six-inch barrels. Can't be sure they aren't M-1917 or other New Service guns, but I think, Official Police. I can't see the front sights well enough to differentiate. But I THINK those are Colt .41 frames, not .45 frames.
I love the Mannlicher-Schoenauer and had a M-1908 8X56mm that I really liked, but ammo was hard to find. Besides Ramar, Dr. R.C. Andrews used M-S rifles as well as Savage .250 M-20 rifles. I was a big fan of his, although he died when I was a kid and I never met him.
I guess my pick for a sleek rifle is either the Winchester M-70 Fwt. Classic currently made or a fine classic rifle on a Mauser or M-70 action stocked by someone like Dale Goens.
As for the Model 64, the fancier Deer Rifle appeals to me more than the basic gun. It's in a catalog page pic above.
Ditto for the M-71 .348 fancier version.
I also admire classic British magazine rifles made on Mauser actions by Rigby or H&H.