As a back drop to Geralds feelings towards BKL, I will not miss them one single bit.
Most all of my other modern rimfires have been set-up with quick detach rings on a Weaver base, so to me, Hotrod9mm's new supply of Weaver single piece bases for ALL of the 452 and 453 Models INCLUDING the Lefties (Me) AND the Stainless (Nickel) finished Styles is perfect timing.
He even ensured that the spacing was correct in order that the 10/22 guys, such as myself can cross over a scope on Q-D's to a CZ and back with the spacing matching perfectly. Same with His answer for "Other" popular brands (you'll have to insert the brands at this time)

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Now I can quickly and easily change optics on all of my favorite guns.
I tried those BKL 257's on my Anschutz, they are the last and only set I will ever buy.
They do not hold center, AND they instill stresses into the scope tube just by virtue (there's an oxymoron) of their design.
I also tried the Brooks 2-Piece Weaver adapters, for over a year I thought my Varmint in HM2 had some sort of terrible issues when all along it was those bases moving and shifting around.
Quickest way I know to accurize your CZ is to install a one piece Weaver adapter base that was designed and clearanced properly in the first place with 6 screws that promote and hold a perfect center. Soon as I can, I'll post a pic of the BKL's at the bottom of my trash can!

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Not necessary, Greg, I have the same picture...
(PS: Your PM box is full.)