I use the AREA 419 clamp on rails for all three of my CZ 457s. I had bought an aluminum rail from some else for my
Kimber 82G and it uses set screws to drive down into the receiver. That's not a huge problem because I put #8 lead shot under the heads to protect the gun. I still ended up with a BIG problem. The front of the aluminum rail is a little sloppy and it's cross section is very thin once you remove material for the Pic grooves and the dovetail. The net result was the front of the cheap aluminum rail was bending upward noticeably.
A couple of mm.
I just bought a Murphy the other day for my 82G and the fit to the dovetail was very close. I still had to put lead shot under the brass tip set screws
to minimize any color transfer but it is now a solid set-up. I couldn't see the logic in spending extra money on the Ti rail but am very happy
with my rock solid S.S. 82G scope rail. Truly I wish all rails clamped on like the AREA 419 but until they do..... Murphy it is.
BTW.... I had it in about 4 days.
To be clear, I'm perfectly happy using AREA 419 rails on my CZ 457s. They are less expensive, plenty robust and wont damage the top of your receiver. The 419 clamping screws never touch your gun. They reach across the top to provide a rock solid clamping action. I would also get a Vudoo bolt knob, Anarchy Outdoors extended magazine release ( longest made ) and an ACE #21 or #22 trigger shoe
for your 457.