Yard Sale Leupold

I found a Leupold M8-4x pistol scope at a yard sale. Decided that, for the price, it would be a "no brainer" to drop into my Hunter. Stopped by Green Top on the way to the range Saturday, they recommended Burris scope rings. I bought them and went on to the range. No matter what I tried, I couldn't get the Burris Rings to work. I couldn't even get the screws that fasten the scope to the the rail to go back in. Took them back to Green Top and the clerk couldn't get any set of rings to work. The rings either didn't fit or the scope didn't fit on the rings. Guess my no-brainer turned into a major task.