I have also used the Picatinney CZ rail for my 527M, which is a different beast with the fixed iron sights. I removed the rear iron and tried a few scopes, first a WalMart Simmons with supplied CZ rings, But that scope lost lock and wandered everywhere. I was gifted a Bushnell scope that was quite good, and tried the Picatinney with Weaver Low Mounts, which came out looking like this. A Marbles folding rear sight was added, courtesy of my local gunsmith in Mesa, and you can see how low the clearance is on the scope bell. Bolt handle clearance was tight. So, yes, the Picatinney rail CAN be useful, even though I've removed mine, and went with straight irons. Have fun with your new blaster, and post pics when done, please? Like that putty idea.