Sear not releasing the hammer in SA mode on CZ 97BD

[Reload06]

Hi all,

I have a new CZ 97BD with less than 200 rds through it. The sear is not releasing the hammer in SA mode.  I read PHKsCZ post (6/24/2009) and responses.  All agreed that Double Pedro's response was correct.

There are one of three possible fixes.
1)the DA break point needs to be advanced a bit  or
2)the SA break point retarded or
3) add a comp hammer to change the timing (for the better).


I contacted the folks at CGW but they said the hammer fix may not always work. 

They suggested welding the sears lower leg (to add metal) to advance the SA timing.  I understand that.  Add metal to the forward face of the lower sear arm will lift the sear higher releasing the hammer.  I guess alternatively one could add metal (via welding) to the aft facing surface that contacts the lower sear arm to accomplish the same thing.

Both those fixes require adding metal.  Schmeky suggested a bevel cut on the disconnector but I do not understand how that would help push the sear arm aft. 

Can anyone explain how 1) and 2) above can be performed by removing metal?
Can someone direct me to the picture of the beveled disconnector?

Thanks

Reload06

[dlidster]

Less than 200 rounds . . . Is this a new gun or a new-to-you used gun? If it's new a call to CZ-USA would seem to make a lot of sense.

[SPO1SHADOW]

I believe the disco comment is GCW's latest mod to improve the double action and should have no effect on the single action as long as the gun is resetting properly. I have seen this happen only twice in an unmodified factory gun and in both occasions the rear of the trigger window needed to be opened up to allow more trigger movement to the rear. The frames are cast and in the 2 guns I had the occasion to look at the sharp edge in the rear of the trigger window in the frame had not been addressed at the factory. It took longer to take the gun apart than it did to remove about 1/16th out of the rear of the window that allowed the trigger its full rearward travel. I am not saying this is your problem but if you see the rear of the trigger contacting the rear of the trigger window it could be. Welding the front leg of the sear would no doubt fix the problem also but the first thing to do is find out what is out of spec. The Race hammer has much shorter hooks but it also changes the timing and could make the situation worse or better depending on which component is out of spec. The only thing we know for sure right now is that the trigger bar is not moving to the rear far enough to release the hammer.

[schmeky]

SP01SHADOW is 100% correct when he stated:

I believe the disco comment is GCW's latest mod to improve the double action and should have no effect on the single action

We did not have sufficient information from the OP at first, but when we did have sufficient info, we indicated the welded sear was the proper path to alleviate the issue.   The disco has absolutely nothing to do with the trigger bar running out of travel in SA.

Golden rule in gunsmithing:  always  modify the cheapest part, first. 

[Earl Keese]

I understand that the solution is to modify the sear, but which part or parts are the actual cause of the problem? If it was an out of spec sear, the easy fix would be to replace it, so I assume it isn't the sear itself that's the culprit. SP01SHADOW already mentioned the trigger window, what else would limit travel? Sorry if I'm being dense, just looking for knowledge. Also, on a new gun, why not send it back to CZ for warranty repair/replacement?

[SPO1SHADOW]

Unless you just can't stand the thought of being without the gun for several weeks sending it back would be the best thing to do. A BD is not an easy gun to work on unless you have some experience disassembling/reassembling decockers. I love my 97B but had it had an issue out of the box even though I am sure I could fix it I most likely would have still sent it back. It could have other problems that need to be addressed along with this one.

[Tok36]

Interesting stuff.

[Reload06]

Hi all,

Yes the gun is new.  I don't want to pay for shipping for something I could fix myself.    I have a few SP-01s so I went back to look at them also.  The sear lifts just barely enough to release the hammer on those also.  I do not know why they cut it so close on that detail.

Enough ranting ... Much thanks to all that posted replies.  Excellent insight by all and you did it without pictures !  Very impressive.  Yes the trigger bottoms out on the frame before the sear releases.  No burs or flashing there though. Could be an out of tolerance hammer, trigger bar or a host of other parts, even the trigger.   

The back face of the trigger is a little rough.  I think if I am going to grind, I will start there.

Thanks again.

Reload06