Look for a B-Square scope mount. I have one on my 12 gauge and I like it. It mounts on the gun by removing the 2 trigger screws, installing the mount, and using the 2 screws supplied with the mount.
There will be appx 1/2 inch space between the top of the reciever and the bottom of the mount. I use a cheek pad to raise my line of sight and don't have any problems.
I paid $40.00 for mine, IIRC.