This might help. Really good article. Check the chart in the middle of the page.http://www.lasc.us/rangingshotrifleairgunscopes.htm
Burris CS has been outstanding for me. I have a 3-9 x 50 mm E1 scope on my M70 30-06 which has been an excellent hunting scope. I have not had a Burris scope on an air rifle.
Recently I've looked into Burris scopes. I've dismissed them before, but their no questions/forever warranty has peaked my interest. Their line up runs from about $150 to over $1,000, so they have something for every budget. The down side is most their lower priced scopes are either fixed parallax or only adjustable to 50 yards. They do have some that go down further, just on pricier models. I can't seem to find anyone who uses or used a Burris scope on an air rifle. I've been entertaining the thought of buying one and testing on a springer. From what I've read, their robust and track well. I figure the worst could happen is it fails and only have to pay postage for them to fix. They do stand behind their product from what I understand.If anyone has expirence with Burris optics please share your expirence. Not discounting other brands, but there's little information regarding Burris. Thanks for reading, take it easy.