I bought a pair of Warne rings for my 527, I mounted them this evening. The rear ring on the CZ factory rings has a shallow recoil lug that fits into a corresponding slot in the base. The Warne rear ring has a screw set where the CZ lug would be to accomplish the same purpose.

The screw is too large and doesn't fit the slot, so I mounted the rear ring without it- this after chasing the screw head with a file, etc.

Am I going to run into problems with the lack of a recoil lug? The rifle is chambered in 223.

you might but It wont be too bad, a guy sold me a set of clamp on rings for MY 550 7X57, the scope came off and whaked me in the forhead. I got a set of warns made for the 550 and they have been fine You might give warn a call and tell them whats going ,on probably got the wrong screw in you package. They are nice folks ,don't have a number but they are in clackamans oregon, I picked up my rings at the shop...tj3006