Colt Series 80 Thumb Safety Problem

[yohann160]

I have just noticed this after a thorough cleaning.

1. I manually #### the hammer (2 audible clicks)
2. I engage the thumb safety.
3. I engage the grip safety
4. I pull the trigger. Problem: as I pull the trigger I notice that the hammer creeps forward a tiny bit.
5. I look at the series 80 firing pin safety lever and I can see that it moves up and down as I squeeze and release the trigger.
6. I make sure I am not touching the trigger and that the grip safety is still engaged. (Grip safety position doesn't matter I have tried it both ways)
7. I disengage the thumb safety and the hammer falls to the first #### safety. (It does not hit the firing pin)

Repeat steps 1-5

8. Upon noticing that the hammer creeps forward a tiny bit, I manually press it down again and I can distinguish an audible click.
9. The grip safety still engaged, I disengage the thumb safety. Nothing happens.
10. I pull the trigger and the hammer falls and strikes the firing pin.

What is the problem? Did I improperly perform detail strip reassembly (firing pin safety)?

-The parts are all stock circa 1986.
-I don't recall having this issue before I recently detail stripped it for maintenance.

 

[m39a2]

The only thing the grip safety does is block the movement of the trigger bar. I would replace the grip safety and replace the manual safety thumb safety. It would appear that these part were either ill fitted when the gun was put together or have worn from use.

Scott

 

[alpining]

Helpful pics of how the thumb and grip safeties function:

w ww.thehighroad.org/showthread.php?t=231096


I don't know much about Series 80 so I may be mistaken, but I am pretty sure FPBS will not affect hammer movement: It simply blocks the firing pin.

If your hammer is creeping forward during trigger pull before the sear releases, you've got negative hammer/sear engagement. Dangerous condition, requires attention. This is consistent with your #8 observation. With positive sear/hammer engagement, the hammer should move slightly rearward during trigger pull before sear release.

Hammer fall on safety disengage, sounds like it might be a thumb safety fitting issue. This wasn't happening before your detail strip?

Did you tinker with the sear nose and/or hammer hooks? It's possible that this is all due to the negative engagement identified above. Actually, the more I think about it, the more that makes sense. With the thumb safety on, your trigger pull moves the sear nose almost off of the hammer hooks. Negative engagement means the sear nose won't reset back into the hooks when the trigger is released, so the slight shock of the thumb safety disengaging bumps the sear off of the edge of the hammer hooks. But it only falls to half ####, as the sear isn't being pushed its full range by the trigger bar. And this is consistent with proper lockwork operation if you manually reset the hammer.

Maybe. Trying to diagnose over the internet!

 

[yohann160]

If your hammer is creeping forward during trigger pull before the sear releases, you've got negative hammer/sear engagement. Dangerous condition, requires attention. This is consistent with your #8 observation. With positive sear/hammer engagement, the hammer should move slightly rearward during trigger pull before sear release.

Hammer fall on safety disengage, sounds like it might be a thumb safety fitting issue. This wasn't happening before your detail strip?

- I honestly don't recall it happening in the past.

Did you tinker with the sear nose and/or hammer hooks?

- No I didn't. I just cleaned them with a rag.

It's possible that this is all due to the negative engagement identified above. Actually, the more I think about it, the more that makes sense. With the thumb safety on, your trigger pull moves the sear nose almost off of the hammer hooks. Negative engagement means the sear nose won't reset back into the hooks when the trigger is released, so the slight shock of the thumb safety disengaging bumps the sear off of the edge of the hammer hooks. But it only falls to half ####, as the sear isn't being pushed its full range by the trigger bar. And this is consistent with proper lockwork operation if you manually reset the hammer.

- How could this happen? Is it wear?

 

[Heddok]

Before you go any further read this!! http://www.cylinder-slide.com/1911safetyck.shtml All 1911's must pass these safety checks... no exceptions.

What's happening with your gun is that the thumb safety lug is too short and is allowing the trigger to move the sear even though the thumb safety is on. Then when you release the thumb safety and the hammer falls this is extremely dangerous, never should you depend on the safety ledge (AKA half #### notch) to save your bacon. When the thumb safety is on it should prevent all sear movement period... why or how it came to be no longer matters.

When you manually pull the hammer back you are allowing the sear to rengage the hammer hooks fully, this is the click you are hearing.

As also pointed out the sear/hammer engagement may be less than optimal in either case you need this gun properly assessed by a 1911 gunsmith and a new thumb safety fitted at a minimum.

 

[yohann160]

Before you go any further read this!! http://www.cylinder-slide.com/1911safetyck.shtml All 1911's must pass these safety checks... no exceptions.

What's happening with your gun is that the thumb safety lug is too short and is allowing the trigger to move the sear even though the thumb safety is on. Then when you release the thumb safety and the hammer falls this is extremely dangerous, never should you depend on the safety ledge (AKA half #### notch) to save your bacon. When the thumb safety is on it should prevent all sear movement period... why or how it came to be no longer matters.

When you manually pull the hammer back you are allowing the sear to rengage the hammer hooks fully, this is the click you are hearing.

As also pointed out the sear/hammer engagement may be less than optimal in either case you need this gun properly assessed by a 1911 gunsmith and a new thumb safety fitted at a minimum.

Imagine that. I'm guessing there aren't many 1911 guru's around Quebec City. Ha.

 

[yohann160]

Well, I just swapped the original safety for one I had laying around. Now it works just fine.

 

[alpining]

Well, I just swapped the original safety for one I had laying around. Now it works just fine.

Good to hear - Be sure to check that negative hammer / sear engagement issue. Regardless of thumb safety function, that is a dangerous condition.

That's a good comprehensive safety / function check that Heddok linked. The safety system on the 1911 is just that: A system. Each of the 'safeties' do something unique to make the gun 'safe', and they need to be assessed independently as in the link.