I got my youngest son a 200 .270 for Christmas and was trying to get a Prostaff 3x9x40 mounted on it before a hunt next weekend (early CHRISTmas present).
After several trips to Academy and Gander, I ended up with Gander's Guide Gear Weaver-style 2 peice extended base #402. They didn't have the real Weaver bases so I had to pay 3x more for the store brand. Weaver's $4.99 ea. Guide Gear $14.99 ea.
These were the only bases I could find to fit the long action with the Nikon scope.
While the scope clears the action, I probably should have gone with the taller rings.
Thought I'd share and hope to save someone else a lot of leg work and frustration.