1911- Safety Issue

[castrotikon]

So, somewhat tangentially related to a post I had in general a few days back: I've got an early 90s Springfield Armory GI style 1911 I picked up. The gun is obviously well worn, has a few after market changes I could tell made to it: trigger and extended slide release. Due to the age, I decided to replace a few parts myself. Namely, the trigger, the sear spring, and contents of the mainspring housing. After completing re-assembly and before putting the slide on, I was doing a function test and noticed a problem: when I have the thumb safety engaged AND the grip safety pressed (this does NOT happen if the grip safety is not pressed), if I squeeze the trigger the hammer drops ever so slightly. Not enough that it is near the half cock notch but enough that there is an audible *click*. Once it is in this position, I cannot get the safety to move without resetting the hammer. Strangely enough, when I put the slide back on, the problem went away. Still, I don't feel that is normal behavior.

So the burning question is: did I unintentionally mess something up in the process of replacing parts or is there something else going on? In my defense, this problem could have been there previously and I just noticed it. I don't see how anything in the mainspring housing would be related to this which leaves the trigger and the sear spring. I did not modify the sear, disconnector, safety, or hammer in any way.

[10x25mm]

This behavior is not normal.

The behavior does not occur when the slide is mounted because the disconnector is involved. With the slide mounted, the disconnector's rise is limited by the depth of the disconnector pocket in the underside of the slide. This suggests that the transfer flats on the bottom of the disconnector are not exactly parallel - thicker at the bottom than at their top. As your disconnector tip wears, this behavior could occur when the slide is mounted. And then the hammer might drop to the half cock notch or, in the worst case, to the firing pin.

The behavior does not occur when the grip safety is uncompressed because the grip safety blocks the trigger's travel. This suggests that your grip safety and trigger are uninvolved and correct dimensionally.

Something is wrong with your sear, hammer, and/or thumb safety geometry. Do these three parts appear to be original? Has anyone attempted a 'trigger job' on the pistol by grinding the sear surface on either the hammer or the sear?

The hammer should have a flat sear surface which lies on a plane extending out from the centerline of its axle pin. The sear's sear surface should be either a flat surface parallel to the hammer's sear surface, or a compound surface. The compound surface is the flat surface parallel to the hammer's sear surface, modified by a small 45 degree cha**** on the hammer side. That cha**** (often called a secondary sear angle) could be too large, the hammer's sear surface could be worn out of flat, or the sear prop surface on the safety could be too far to the rear.

Access to trigger adjustment pins or an armorer's block is essential to diagnose your pistol's sear interface. If the sear interface is found good, a replacement safety is in your future.

This behavior really requires careful examination by a competent 1911 gunsmith.

[pkuptruck]

gonna guess two things.

1. It is an adjustable trigger ( and it is adjusted WORNG)
2. It was a used and already modified safety.

But, pretty sure its number one. seen it a bazillion times.



As 10x said... have someone VERY familiar with 1911's check it out.

[XDM 40 cal]

I agree with both Pkuptruck and 10x25... The hammer should never move till the Grip and sear safety are disengage...

[castrotikon]

gonna guess two things.

1. It is an adjustable trigger ( and it is adjusted WORNG)
2. It was a used and already modified safety.

But, pretty sure its number one. seen it a bazillion times.



As 10x said... have someone VERY familiar with 1911's check it out.

I'm leaning more towards 10x25's response that the trigger and grip safety are unrelated to this. The trigger just has an over travel screw. Not an expert, but nothing about the trigger movement or setup seems out of the ordinary so I'm really leaning towards something with the hammer and sear interface.

The safety and hammer are almost certainly original. The sear I'm not entirely sure on, given that the trigger that was in it when I got it seemed to have been roughly fit, I would not be surprised if the same owner also tried to replace the sear or grind it down. I also would not be particularly surprised if the parts are just worn down at this point. Anyways, going to place a couple of calls later this afternoon but it sounds like a safety/hammer/sear replacement is in my future.

[pkuptruck]

I'm leaning more towards 10x25's response that the trigger and grip safety are unrelated to this. The trigger just has an over travel screw. Not an expert, but nothing about the trigger movement or setup seems out of the ordinary so I'm really leaning towards something with the hammer and sear interface.

The safety and hammer are almost certainly original. The sear I'm not entirely sure on, given that the trigger that was in it when I got it seemed to have been roughly fit, I would not be surprised if the same owner also tried to replace the sear or grind it down. I also would not be particularly surprised if the parts are just worn down at this point. Anyways, going to place a couple of calls later this afternoon but it sounds like a safety/hammer/sear replacement is in my future.

the 1911 is a finicky lady.


And the trigger most CERTAINLY has a relation to this. I have built and messed with them for over 25 years.

The set screw is NOT an over-travel adjustment. I promise. No matter what it says.. it is not.
It has a direct interaction with the trigger bow, and therefore the sear and the mainspring.

try backing out the set screw, and re-try the safety test. See if anything changes.

[10x25mm]

Partial sear releases in a 1911 are a common symptom of insufficient trigger travel when the thumb safety is disengaged and the trigger is pulled. Application of the thumb safety in a 1911 with a correct geometry trigger group should absolutely immobilize the sear, precluding any partial release, regardless of trigger travel. Or the exact position of the disconnector, when it is up full travel.

[castrotikon]

Partial sear releases in a 1911 are a common symptom of insufficient trigger travel when the thumb safety is disengaged and the trigger is pulled. Application of the thumb safety in a 1911 with a correct geometry trigger group should absolutely immobilize the sear, precluding any partial release, regardless of trigger travel. Or the exact position of the disconnector, when it is up full travel.

To be clear, it functions fine with the safety disengaged. It is only with the safety engaged that it is dropping the hammer slightly. So, if I understand correctly, you're saying the amount of trigger travel should have nothing to do with my issue and the problem lies somewhere in the geometry/connection between the safety/hammer/sear?

I'm not trying to come off as insulting or anything, I'm just kind of confused since it seems like one of you is saying it could be the trigger travel and the other is saying this has nothing to do with the trigger travel.

[JohnJak]

Get it over to Ron at Blackwater.

[10x25mm]

To be clear, it functions fine with the safety disengaged. It is only with the safety engaged that it is dropping the hammer slightly. So, if I understand correctly, you're saying the amount of trigger travel should have nothing to do with my issue and the problem lies somewhere in the geometry/connection between the safety/hammer/sear?

You understand correctly.