I have been wanting to move my swfa 3-15 to my sage rat gun, and now I can. An nx8 would be awesome for a rat gun, but unless you live in sage rat country, it would be hard for me to justify.
I go east a couple times per year to shoot rats, and only use my 17hmr for the prime time (first 3hrs of daylight) and then i start walking the edges of the pivots and shoot my bow the rest of the day
The 3-9 will still be great for rats, that’s mostly what I have used in the past… a little more would be ideal, but unless you’re burning 10k rounds a year shooting rats every day, I would have a hard time spending over 2k on a rat scope
I don’t love the swfa 3-15 for an all around hunting scope, especially if there may be a new shooter behind the gun, but it will be awesome on my CZ