In case you're STILL curious about the 453 trigger...
Hey All...from a previously posted excellent thread and in the helpful spirit of RFC I thought I would RE-post this info as it really is great and well done...so here it is. I will try to re-add the pictures shortly. Sadly the videos have been now made private...maybe that will change. Hope it is helpful. Enjoy!
I whipped up a short video showing the various adjusters, and how the trigger assembly is open enough to make initial adjustments visually.
I've got it set up to break at 2lbs 2oz for hunter class in metallic silhouette now, didn't take very long at all. It's breaking very cleanly, no noticeable creep, and no noticeable amount of over travel. I left just enough room for the sear to merrily whisk on by, but not much more. The trigger-sear engagement is right out in the open, and you can roughly adjust it by eye, and then go by test firing from there. I believe CZs can be dry-fired without worry, but I threw an empty case in there anyway. It was very heavy as set from the factory, with more creep and over travel than you could shake a stick at, but I'm pretty happy with it now!
The trigger pull weight is adjusted with the top right set screw, which also has the trigger spring mounted directly on it, which you'll see in the pics below. The spring is nothing like the one used in the 452's trigger, which is much larger than the 453's spring. The spring you see exposed at the lower left is for the set trigger's operation. Just above that I've marked the set screw for adjusting the amount of pre-travel or sear engagement. Unlike the other two adjusters, this one does not have a lock nut on it. Neither does the one for adjusting the set trigger's amount of engagement. I suppose the fact that the other two are subject to your finger's pressure is what they felt made those ones require a nut to keep the adjustment in place, just a guess. Here's the trigger pull weight screw and spring, with a penny for scale to show just how small it is. You can see the light grease they put on it.
There's a bit of side-to-side wobble in the trigger. I'm not sure how easy it would be to get rid of that. I don't know if it would come apart easily enough to shim it and throw it back together. Didn't take a good enough look at it while I had it out of the stock. Another day, I suppose.
Replace the spring
If you wish to replace the factory trigger spring (the one in the photo next to the penny) with a lighter one, you can find them at any hobby store that sells R/C airplane parts. The springs may be longer than the factory springs, but it can be clipped back to apply what ever spring pressure you like. The springs usually come in a package with other components and linkage for steering controls. You may also have to look through the packaged components to find a spring with the proper diameter.
I was hoping to get the regular trigger to the same pull or lighter than the set trigger, but am unable to at this point. As it is, the regular trigger with the lighter spring is just a touch stronger than the set trigger. Definitely not recommended for a person with a heavy touch. But just the way I like it for now.
Another quick clip, this time from the other side so you can see the set trigger's goodies. This one's a bit blurry, camera didn't want to focus this time, heh.
This pic shows it cocked and ready to fire with the regular trigger, but with the set trigger left alone.
Here you can see I've just started pushing it forward, and the set trigger is just starting to make its way up that sloped edge.
And here the set trigger is set and ready to fire. Once you pull it now, a spring behind the trigger itself launches the trigger forward, and it then kicks off the regular sear and fires. This spring is hidden from view. Actually, you can see this spring in the first picture of this post near the top of the silver trigger.[/edit] It's another small spring, which looks like it might be the same size as the spring for the regular trigger's pull weight. It's just above the hinge for the trigger itself, and obviously pushes that part of the trigger forward.
If you want to disable the set trigger you can screw in the adjuster screw for it until it no longer lets you set it. You can also keep turning it in further than that so that the trigger can't be pushed forward at all if you like. Disabling it in this fashion is enough to make it legal for metallic silhouette matches, by the way. Someone from steelchickens.com was talking with someone at the NRA that deals with silhouette, and according to the NRA guy that was good enough to make it qualify.
The regular trigger's sear engagement doesn't affect the set trigger in any way. They're entirely separate parts that don't touch or affect one another. The screw to adjust the set trigger is what adjusts its amount of engagement. Changing one or the other can't do anything to the other one.
If you're feeling creep, it is because there is still a lot of engagement, as that's what creep is. And the adjuster screw for the set trigger is what determines how much engagement there is for the set trigger. Try this. Cock it and set the trigger, and turn the adjustment screw for the set trigger in slowly, until it trips. Cock it again, and see if you can set it now. I'm guessing it might not set at this point, though maybe it will. At any rate, that'll give you a good point to start fine-tuning the set trigger. You should be able to get it to the point where it will just barely set, and then it'll trip with very little pressure and you won't be able to feel any creep at all. Or to put it another way, you should be able to adjust that screw in far enough so that the set trigger will stop setting, and it will no longer click and stay set. That'll give you a point to back off slightly from, so that it will start setting again.
I might as well paste this reply from another thread into this thread. Has some more detail about adjusting things:
I suggest you loosen all four adjustment screws quite a bit, probably past halfway out. This will give you a trigger that probably feels pretty crappy, but it's just a starting point so you can adjust each one to your liking.
In the thread where I have pictures of the trigger and the videos, you can see that there are four adjustment screws. Each one of them does something that affects how the trigger behaves, but I don't think you can really say that one will affect the other.
Let's go over the labeled screws.
Sear engagement/pre-travel: This screw on the left side of the picture is what adjusts what's commonly called creep. This adjusts how far the trigger has to be pulled before it lets off. The more you loosen this screw, the farther and farther you'll have to pull the trigger before it lets off. The more you tighten it, the distance the trigger has to be pulled will get shorter and shorter. And if you tighten it too much, you won't even be able to cock the gun and have it stay cocked, because the sear will eventually stop setting. You want enough engagement so that the sear will stay set once set, so there won't be any danger of it accidentally letting off, such as when the gun gets bumped, but not so much that the trigger feels creepy and it gets hard to tell when it will let off as a result. An easy way to adjust this one is to back it off much further than you would normally like, cock the gun, and then slowly tighten the screw until the trigger lets off. It is now adjusted just a bit too far, and probably won't even successfully cock anymore. The sear is no longer engaging. Why do you want that? Well, you don't, but what this does give you is an easy way to find out where you do want it adjusted. Now that you have it just a bit too far in, it should be a simple matter to begin backing the screw off a little bit at a time until the sear starts successfully engaging again. So, back the screw off a tiny bit now, and try cocking the gun again. You'll want to have enough sear engagement so it won't go off when you give the gun a good bump with the heel of your hand, at least. But you don't want so much that it feels like you're pulling the trigger a mile before it lets off. This spot should be easy to find after the first step where you kept turning it in until it let off on its own. Once you're happy with this setting, you can move on to pull weight.
edit - If you have trouble with your bolt coming out when you cycle the action, you don't have enough sear engagement. Dial in slightly more sear engagement and this problem should go away.
Pull weight: This screw adjusts how light/heavy the regular trigger feels when you pull it. It will not change any other aspect of the trigger. The more you unscrew/loosen it, the lighter the regular trigger will feel. The more you tighten it, the heavier the regular trigger will feel. This is the only thing it will adjust. It will not affect pre-travel, over-travel, or the set trigger's feel, no matter what you do with it. It will only change how heavy the regular trigger feels when you pull it. Loosen the lock nut and adjust this to your liking, and then lock it down again with the lock nut. After you snug the lock nut down, test it again to make sure it's still feeling right to you. Snugging the lock nut down may move the screw a tiny bit, so you may have to play with it a bit to get it where you want after snugging up the lock nut. Then you can move on to the set trigger adjuster.
Set trigger screw: While you can accomplish a couple different things with this screw, really it only has one function: it adjusts how far forward you can push the trigger. Either this lets you adjust the sear engagement/pre-travel for the set trigger function, or it lets you disable the set trigger. I've heard people say that this screw lets you adjust how light the set trigger is, but, strictly speaking, this is incorrect. This screw really only lets you adjust how much pre-travel there is for the set trigger. You can't really adjust the pull weight for the set trigger, as there is no provision for doing so. I suppose an argument could be made that increasing the amount of pre-travel for the set trigger also makes it feel as if you're making it lighter/heavier, but that's not accurate. All you're really adjusting is how much pre-travel there is before the set trigger lets off and flies on its way to knock the real trigger off so it can release the sear and fire the gun. If you look at the opposite side of the gun and push the trigger forward you can see where the top of the trigger engages a secondary sear and gets set. If you have this screw very loose, you get a lot of engagement between those two parts, and this translates to a lot of pre-travel when you pull it. Tightening the screw allows you to decrease pre-travel. You can use the same trick to set this screw as you used for setting the regular trigger pre-travel. With the screw set very loose, push the trigger forward to set it. Once it is set, slowly tighten this screw up until the trigger lets off by itself. Then, back the screw off slightly from that point until you're happy with how much pre-travel it has. If it's too tight, pushing it forward won't let it set, so you back it off just enough to allow it to set. You don't really need to worry about doing a bump test for this one, as you are only dealing with the set trigger, and you should never set it until you're already aimed and ready to fire, and are about to do so. You'll likely want to have this screw set to the absolute minimum possible, so that pushing it forward sets the trigger and barely pulling on the trigger sets it off. However, if you decide that you don't even want to use the set trigger feature, you can turn this screw in quite far, and pushing the trigger forward will no longer allow the trigger to click into the set position. Or, you could turn the screw in even further, so that the trigger won't even move forward at all, and will only pull backwards to operate as a regular trigger.
OK, so, now you have your regular trigger's pre-travel set just how you like it, probably with no perceptible creep left, and it doesn't go off when firmly bumped with the heel of your hand. And you also have the pull weight set how you like, as light or heavy as you see fit. And you have the set trigger fixed up so that it sets reliably, and goes off when you barely pull it. Now, finally, you can worry about the last adjustment, the over-travel screw.
Over-travel: This will only change how far the trigger is allowed to move. As it came out of the box there was probably quite a lot of movement after the trigger lets off. Loosening this screw will let the trigger move further and further, well beyond the point that it lets off. Tightening it will restrict its movement, not letting it move quite as far. And the more you tighten it, the less movement will be allowed. If you tighten it too far, it is possible that it will no longer let off, as its movement is being restricted so much that the sear cannot be released. How much over-travel you want your trigger have is something that you'll have to figure out for yourself. Some people like a lot of trigger movement after it has already let off, and others like it to stop dead the instant after it lets off, and some like it somewhere in between those two extremes. If you want it to only move a tiny bit after it lets off, you can slightly modify the little trick you used in adjusting the other screws earlier. If you take a look at the picture again you can see where I've labeled the point where the sear and the trigger are engaged, in green text. How much these two parts overlap is governed by how you adjusted the pre-travel screw earlier. What you'll be adjusting now with this over-travel screw is how much distance there will be between the two when you pull the trigger. So, an easy way to do this is to cock the gun, and turn the over-travel screw in until it just barely touches the trigger. Obviously this will stop you from pulling the trigger now, but we're not done. Now that it's touching the trigger, lightly pull the trigger while you slowly loosen the screw. Sooner or later you'll loosen it enough so that the trigger lets off, but at this point it might be so close that the sear could drag slightly on the trigger. This probably isn't what you want. But now you can fine-tune it so that it will pull just far enough to allow the sear to fly by without making contact with the trigger and dragging on it. That'll give you a trigger pull that lets off and only moves as far as it has to, or you can loosen it as much as you like to give you the feel you want. Once you're happy, snug the lock nut up, and test it again to make sure it's still where you want it.
Now, hopefully that all made sense, and you've now got a regular trigger set to your liking, and a set trigger set to your liking.
A safety reminder that I found out the hard way - If you safety the rifle with the set trigger in the "set" position, return the trigger to the regular "unset" position before you take off the safety. Taking off the safety with the trigger "set" gives you a very high probability of an accidental discharge. Fortunately, mine was sitting on a bench rest pointed down range when I discovered this fact. I later checked it with an empty inserted, and it is highly repeatable.
A call to CZ America confirmed this situation. The gunsmith on duty did however, question my terminology when I called this a "design feature" of the rifle.
No knocks on CZ here - I am very fond of my 453 American.