The best chambering in my mind is the 300 savage, it takes well to handloading but its good in factory form too, it gives up next to nothing to a .308, but by virtue of being a couple of tenths shorter in OAL, the lever swing is about 20 degrees less, which makes follow up shots so much easier. The 250 savage is the sweet chambering in a 99 for most deer and smaller game. its virtually recoiless in the 99, and I have several. If you have a smaller person or one who has developed a flinch, the 250 in a 99 is a wonderful gun
I agree, I have two 99s, one is 300 Savage and one in 250 Savage.
I'm using both guns with just iron sights, however the 250 has a Lyman Tang mounted aperture sight on it.
It's amazing how well these old rifles will shoot.
However this does not surprise me about the 300 as I owned one once before and sure took a lot of deer with it.