75B SA questions

[jabate01]

I have acquired a 75B SA with a Armory Craft flat trigger, a CGW adjustable sear and a CGW race hammer installed. Great condition, great price. I'm having problems with the reliability. When the trigger is pulled the lifter does not come up to move the block safety. There for the hammer hits the firing pin, but the firing pin doesn't move and no bang. I have removed the block safety and things seem to work fine. The trigger is adjusted so that I have the full range of pre-travel. I can't figure out why the trigger bar is not moving the lifter. Please Help.

[Tok36]

I would check the Right side Trigger Bar Spring. Insure that it is positioned correctly in the grove/channel on the underside of the trigger bar and that it is providing up tension on the trigger bar. If the TBS is positioned correctly the up tension may need to be increased a bit. For clarity, it is possible that the trigger bar is not making sufficient contact with the lower leg of the FPB lifter arm throughout the single action cycle and this is causing it to move less than required.

You mentioned the pre-travel adjustment set scerw, located at the top of the trigger. Have you backed out the over-travel set scerw, located in the face of the trigger? Though it may not be the cause of your issue i have found that it is a good idea to back out or temporarily remove the over-travel set scerw while trouble shooting FPB and sear issues.

[M1A4ME]

I had a similar issue with a Compact I converted to SAO.

The straight trigger (from CZ USA) and the geometry of the frame/parts wasn't allowing the trigger to move far enough forward to all the lifting arm to reset behind the back of the trigger bar.

Try the pretravel screw (on the front/face of the trigger) first.  That's the easy fix if it's the cause of the problem.  If you screw it rearwards till it no longer sticks out of the front of the trigger and your problem persists you may have to remove the trigger and take some metal off the front of the trigger where it's making contact up inside the frame.  Doesn't take much.  It won't be visible once the trigger is installed.

I guess it's one reason for the little note when you buy parts suggesting having a gunsmith install parts/make changes.  Sometimes things aren't "drop in".  I'll look to see if I can find pictures or my old thread on the SAO conversion I did to that Compact.


Sorry.  Found my thread, but didn't take any pictures of the trigger before/after.  I get in a hurry, fix stuff, it works and I'm so happy I don't take it back apart to take pictures.

http://www.czfirearms.us/index.php?topic=90727.30

[M1A4ME]

There's a spot, in that thread, where I mentioned watching the firing pin block lifting arm "move."

Make sure the pistol is empty (I usually double check, just me).  Then point the gun down/away from you and look at the back of the slide.  You'll see a small open rectangle on the right side at the back.  You can look in that spot and see the firing pin block lifting arm.  It should be down until you pull the trigger.  When you pull the trigger you'll see the back of the lifting arm raise up (to push the firing pin block upwards).

If that arm isn't lifting up when you pull the trigger then it's not resetting correctly with the trigger bar.  On mine, the amount the trigger bar had to move forward was very, very tiny.  That corner of the back of the trigger bar pushed the firing pin block lifting arm to the rear.  When you let up on the trigger the trigger bar moves forward again and if that back corner can't move forward far enough to clear the bottom edge of the lifting arm then it can't push the lifting arm up the next time you pull the trigger.

Sorry, hard to explain without some good pictures.

Just remember, if you do end up having to take some metal off the front of the trigger (up inside the frame) it won't be much.  Reinstall it, check for proper function of the firing pin block lifting arm (do the pencil test).  If it works correctly then you may be able to use the pre travel screw to make an adjustment again.

The pencil test:  Make sure the pistol it empty.  Point the muzzle straight up.  Insert a pencil into the barrel (it will drop down to touch the breech face).  Make sure the hammer is cocked.  Pull the trigger.  The pencil should jump upwards.  Some pistols will launch it out of the barrel, some won't.

Good luck.

[Underwhere]

You can also file away the "wall" on the firing pin block until the pin clears.

[.45 acp nut]

Most of the time when these issues arise it is because the overtravel screw isn't allowing enough travel to fully activate/move the FPB. Tyr backing out the overtravel screw ? a turn and then try the trigger.