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-   -   CZ 452 trigger adjust (pics) (http://glocktalk.com/forums/showthread.php?t=1465276)

Berto 01-16-2013 23:50

CZ 452 trigger adjust (pics)
 
Since I've had my CZ 452 ZKM 2E in .17hmr, I have really enjoyed it's accuracy. I typically get under an inch for 5 shots at 100yrds...which is very good, but I absolutely know it is more accurate. I can tell I am muscling the gun around too much, fighting a stiff trigger.
I don't have a trigger guage, but I have a good idea this one is over 5-6lbs. It has a little takeup, which is fine, but it's just a stiff trigger. You pull, then pull a little harder, then pull a bit more before it finally breaks. All while maintaining breath control and scope picture. Sometimes I have to stop and start over because it takes too damn long to get the shot off.
So I'm fixing the friggin trigger.

A little research indicated this was a fairly straightforward deal;

The trigger is already adjustable, but general feedback lead me to conclude it wouldn't be enough since the factory spring is nuts-heavy.

I pulled the barreled action from the stock (yes, it's beechwood, not walnut) and went to work....

http://img23.imageshack.us/img23/428...ggerjob001.jpg

Pretty simple, trigger, sear mechanism and trigger strut with spring that probably belongs in the valvetrain of a car.
You can see the factory had it set pretty stiff with the adjustment nut actually tightened almost all the way down, too. Backing it all the way off would have dropped about 1/2 to a full pound off the pull....not enough.
http://img62.imageshack.us/img62/154...ggerjob002.jpg

I had done a little snooping around my local screw supply store (Tacoma Screw), and found a nice little spring of similar dimensions, but much lighter spring rate. It's a # 154 on their spring chart.

Here, you can see it above the stock spring. Also, the drift pin I removed to free the strut, the washer for the adj nut (which also indexes to prevent the nut from loosening) and a molly bolt insert I use for dry-firing in rimfires.

http://img855.imageshack.us/img855/7...ggerjob003.jpg

A kit is available with different springs and shims to eliminate the creep or takeup. I actually like a little takeup, especially with a light trigger that I'm going for, so I didn't mess with shimming the front pivot of the trigger. Just a spring swap.
Easy.

The trigger is back together now, lighter spring installed.
I inserted the bolt and checked for pull weight, reset and insured the trigger was safe from being jarred or bumped.
No issues.
....and it's NICE, about a third of what it used to be. Maybe 2lbs and crisp.

http://img24.imageshack.us/img24/315...ggerjob005.jpg

I will actually loc tite (blue) the adj nut and assembly screws when the action goes back into the stock. The bbl looked fine at the forend too, it's free floated to about 2" ahead of the front action pillar, which should be right. I've heard that they often have too much contact from the factory.

Wish me luck.:supergrin:

Bill Keith 01-18-2013 08:33

Do the bullets go Bang with the lighter spring set up?

CanMan 01-18-2013 11:35

Good job & great pics! I swapped out the spring in one of my 452 Americans. It made a huge difference in pull weight + made the little bugger much more fun to shoot. I haven't had a light strike or a 'dud' since changing the spring out... think I'm good to go. I used a YoDave trigger kit from a guy on RimfireCentral. I keep looking at the shims wondering how much benefit I'd see by using one.

Berto 01-19-2013 03:31

Quote:

Originally Posted by Bill Keith (Post 19880185)
Do the bullets go Bang with the lighter spring set up?

Yes. It has no effect on the firing pin strike.

Berto 01-19-2013 03:34

Quote:

Originally Posted by CanMan (Post 19880856)
Good job & great pics! I swapped out the spring in one of my 452 Americans. It made a huge difference in pull weight + made the little bugger much more fun to shoot. I haven't had a light strike or a 'dud' since changing the spring out... think I'm good to go. I used a YoDave trigger kit from a guy on RimfireCentral. I keep looking at the shims wondering how much benefit I'd see by using one.

The shims would just eliminate or minimize the amount of creep/takeup in the trigger before you release the sear.

Berto 01-19-2013 17:17

I made a quick run to range today, the gun works fine, trigger is a HUGE improvement.

http://img571.imageshack.us/img571/5416/czak001.jpg

I still need to loc tite the action and trigger adj screws down, but everything seems in order. POI is 2" lower at 100yrds though, but I'm also using different ammo today- Fed Premium 17gr VMax.

1st one went 9/16" for five shots, second, an even inch.

http://img248.imageshack.us/img248/768/czak002.jpg

Looking forward to a more thorough workout after I cince and loc tite everything...but very happy with trigger now.


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