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CM84E trigger behavior

Posted: Tue Aug 14, 2012 10:03 am
by Kel P
After firing a live round through my CM84E, I've been able to leave the bolt closed and still dry fire (just the electronic mechansim with no firing pin movement). But recently after some trigger weight adjustments (lighter), this dry firing does not work. Or, rather, there is no trigger click on this next squeeze, but it does click on the *release* of that squeeze. Increasing the trigger weight adjustment fixes this but only if I crank it up high well past 150g or so. I am using the medium spring. Did I break something?

The gun is still safe and legal, since any time I load a bullet or empty case, having cocked the firing pin mechansim by opening/closing the bolt, the electronic firing occurs on the squeeze. But I would love to have the convenience of being able to dry fire in between live rounds, a habit I developed that is productive for me. In its current state, I have to cycle the bolt (thus cocking the firing pin mechanism). And depending on the ammo, the empty case might get flung out and I'd need to reinsert a spent case. Small inconvenience. I'm more concerned that something is amiss mechanically (or electronically, but that seems unlikely).

Thanks for any input.

Kel

Posted: Tue Aug 14, 2012 1:22 pm
by flolo
Do you use much solvent/ oil when cleaning the gun?
Maybe there's some oil or dirt on the microswitch ( which is on the trigger assembly just below the chamber) which prevents the switch from moving back in its original position? You also can control this: new battery?
Too much twisted trigger blade( light beam prevents release) ? Spring too heavy for the desired trigger weight?

Posted: Tue Aug 14, 2012 2:29 pm
by David M
If the second stage point (small allen screw on top rail of trigger assy) is set too fine, the trigger will not reset the micro switch all the time if the second stage weight is reduced too far.
Remove trigger assy from pistol.
Fit electronics to trigger to dry fire (off Pistol)
Backoff screw 1 turn, then slowly turn screw in until solenoid fires.
This is trigger point, backoff screw 1/4 to 1/3 turn to induce some slack.
Re assemble pistol.
Reset trigger weight's , first and second stage to liking and test.

Posted: Tue Aug 14, 2012 3:27 pm
by flolo
If(!) it's the two stage trigger! On cm162, you're right.

Posted: Tue Aug 14, 2012 7:10 pm
by Kel P
Mine is single stage. But to David's point... even with one "stage", if I have the rear stop point of the trigger set too tight to the firing point, I might be keeping the micro switch from resetting. I will check this when I get home tomorrow, on the road currently.
Thanks,
Kel

Posted: Wed Aug 15, 2012 2:19 am
by David M
My mistake, that is what you get for answering posts at 5am.
But the same things apply to the free pistol, if the trigger does not return fully it will not reset.
If lightning the spring has caused the problem, check that the trigger is clean and free. Some shooters have put a trigger stop screw in the trigger bar, make sure that there is some after travel.
A clean of the switch with a good electrical spray cleaner will not hurt. Also check that the battery is a a sufficent power level.

Posted: Thu Aug 16, 2012 10:34 pm
by Kel P
Interesting results. Apparently, when I do a live fire or a dry fire in the shooting position (basically, any time I squeeze the trigger with full sight alignment and belief that the chamber is loaded), I stop increasing the squeeze force when the shot fires. The effect of this is that the microswitch does not reset.

The light bulb went on when I dry fired on the bench, just squeezing with an empty cartridge loaded, but not in the shooting position. In this case, the next dry fire worked fine. After some puzzling, it became clear that in a bench dry fire, I was squeezing well past the click, whereas for squeezes in the shooting position, I have developed a habit of not squeezing through.

I shall break this habit, as it points to a creeping/stopping trigger squeeze. Not that I ever find myself doing that! Nooo.

Kel