The topic of plastic guide rods came up frequently on the CZ Forum, where I participated for years.
Many CZ compact owners (which use small, full-length guide rods) felt the plastic was bad -- although they are perfectly functional -- and started looking for metal replacements.
CZ USA offered a metal guide rod for the steel-framed compact, but warned against using them in the alloy-framed models. Some did, anyway. All seem satisified.
The last I heard, CZ USA said that it was noticing some frame damage (on the receiver stop, where the head of the guide rod rests) on some alloy-framed guns when a steel guide rod is used. I have had many CZs, still have a couple, and several clones -- all use whatever was "stock" from the factory.
As I understand it, the guide rod in any gun is NOT a high-stress part. It would appear that it's primary use is to hold the recoil spring in place during assembly -- with the slide and dust cover doing the job once the gun is assembled. I think the concern about plastic guide rods is generally misplaced. (I've seen others open up the end of the slide, normally sealed, on the full-size CZ-75B and install a full-length guide rod there, when a shorter one is normally used. These same folks sometimes claim improved performance and, perhaps, improved accuracy. Again, I think they attribute too much to the role of the guide rod in a hand gun.)
The brass guide rod was NOT my idea -- I just passed it on. I'm sure stainless steel will work, too -- but may be HARDER than some of alloys used in some frames. If you want to use a metal guide rod in your gun, just be sure that the frame is harder than the guide rod. Alloy-framed guns could have a wear issue, over time.
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