[Big-Dummy]

On the 452 to reduce the creep or trigger travel is was necessary to reduce the contact surface between the firing pin and sear.

No. Creep is removed by reducing sear engagement, which is the contact between the trigger and the sear.

 

[Big-Dummy]

Cool and thanks lefty222!

I've been looking for a full (factory?) drawing of all the trigger parts together
so I can study them to know where to stone, polish, and/or modify things.

Should not have to stone anything. The sear engagement is adjustable. If it is anything like the 527/550 triggers, the engagement surfaces are pretty smooth already. If you want a lighter pull, I think you are going to need to install a lighter spring, which might be a challenge, as it looks like you need to remove the trigger blade to get at it.

 

[Big-Dummy]

What I'm about to share doesn't exactly or perfectly fit this discussion, but for some of you it could be very relevant? At the following link is part a discussion about "Mr Fly Triggers" and a vertical stringing problem. I've never heard of this before, but I think what's being said is that (at least with the "fly trigger", but I'm thinking possibly with any that are very light?) if a trigger is too light in pull weight, you could end up with a vertical stringing issue? In basic terms, the solution according to the comments, was to fine tune the trigger at the range after the work that made it so light. Sounds like great advise to me, especially if any of you find out that some of this vertical stringing ends up applying to your 457's.
https://www.rimfirecentral.com/forums/showpost.php?p=9796305&postcount=16

I don't know about that. Benchrest triggers are pretty light, and those guys shoot some amazing groups.

 

[Big-Dummy]

Big-Dummy, it's not my intention to argue with you or anyone else here, yet I feel the need to rationalize or explain more about my earlier comments, especially after the things you've said.

#1, The link and comments I made about the Mr Fly Trigger (& vertical stringing). Maybe I didn't explain well enough that I did not understand how or why that happened, or was "an issue" as djdilliodon wrote. I was only posting the link and mentioning it in case it had something to do with the issues at hand in this thread and could possibly help. And... Yes, I am well aware that many shooters, especially the BR guys, have extremely light trigger pulls without such issues. Maybe the thing I posted about is only specific to the Mr Fly trigger? I just don't know enough to say.

#2, Stoning (honing) trigger parts has been around for ages. "Back in the day" there were little to zero aftermarket trigger parts that the average person (or even a gunsmith) could "drop in" to lighten their trigger pull. The majority of the time gun owners would take their firearms to gunsmiths who'd then "fine tune" things such as the sear engagement area(s) and hammer notches (in those firearms that have them), etc. With my 7.25" satinless Browning Buckmark Contour URX pistol, I only made a very limited number of very light passes with a fine-stone (on the hammer notch and sear engagement surfaces) which took the trigger pull from roughly 4.5 pounds down to about 2.5 pounds. No new springs, or any other parts needed to be installed for this reduction. Obviously, there are many different styles of trigger systems and every design will respond differently to such stone work, but in most cases there will be some improvement. With that said, many, many passes using the same fine-stone did almost nothing on a newly purchased Ruger MK-IV Target pistol. I got at best a 2-4oz improvement. That trigger design seems more dependent on the sear spring tension (imho) given how a (custom - from a parts drawer) spring change dropped the trigger pull by a full 2-pounds on my other MK-IV (Competition), bought at the same time (but did no stone work on).

I haven't touched the trigger on my CZ-457 Varmint (in any way, yet), but I have little doubt some stone work will improve things, to what degree I just don't know at this time. With that said it's also possible it may respond much better to a spring change like my MK-IV? Even with an "adjustable sear" stone work (or "trigger parts polishing") can reduce friction (or with more work, "change engagement geometry") thus improving the trigger pull. Time will tell if I even need to attempt any stone work on my 457. I know one thing, I'd rather take some calculated chances doing stone work, verses buying some $150+ aftermarket trigger assembly (if I couldn't "adjust my way down" to where I want to be)!

CAUTION! Stoning/honing trigger parts can be Extremely DANGEROUS!
As I said above, very few, super light passes on my Buckmark made a huge reduction. I was expecting an ounce or two but instead got 2 pounds! If you're going to attempt this stupidity as I did ("calculated stupidity" in my case), start out with baby steps! Better yet, take your gun to a professional! You've been warned!

"Stoning" is a method of slowly removing material to reduce sear engagement. This is not necessary on a trigger that has adjustable sear engagement. You should follow your advice and take your trigger to a professional, as at least from what you have posted you do not have adequate understanding to safely undertake a trigger job on your own, and certainly do not try it if you do not have a jig to keep the angles intact.

 

[Big-Dummy]

The "issue" with the Fly trigger is that it can drag on the striker, causing inconsistent ignition and thus, vertical stringing. It's just a quirk of how the Fly was designed, and shouldn't be an issue with other triggers.

Polishing the flat behind the angled sear engagement surface on the striker will fix that. That is why it is there, to prevent the sear dragging on the striker. If you need some clearance, some 400 grit and a flat surface like a small file will take care of that, but a felt wheel and some green polishing compound will make a mirror surface.