Mount/Ring question

[JDBraddy]

I bought a used BRNO Mod-2E (Similar to CZ 452 Special Trainer) intending to use it for silhouette, I pulled a Leupold 6.5-20X40 EFR off another rifle to mount on it, when I realized the rings wherent going to be tall enough, or let the scope go foward enough for the objective bell to clear the rear sight. The only mounts I had that would do it, was a BKL 4" one piece that I took off one of my airguns, the only problem with this is the one piece base spans the ejection port interfearing with ejected rounds, they bounce off of it, and wind up right back in the ejection port. I was able to shoot it this way, but got terribly annoyed having to turn it upside down and shake out the empty each time. So I'm asking all you silly-wet shooters, specificly what mounts/rings/risers do I need in order to clear the rear sight and still have a good head position in the standing?

[Jason]

I used BKL 257A rings on my CZ 452 Varmint when I shot it for silhouette. Its stock doesn't drop off like the trainer and lux models, though.