Sightron discontinued the 3-9x36 Big Sky when they reconnoitered their whole scope line.
I had one on a 17HMR that my son now owns. I liked the scope. Small, light, excellent glass, front AO. Perfect for a rimfire. I like the Big Sky scopes. Consider them a good value if you buy them at discounted prices. They have there niche IMHO. All that said, Kahles is my favorite!