Correcting a Bump Fire Condition on 2011

MEGARMS · Mar 17, 2019

Had this 2011 custom built for me in 2018 - The trigger was about 2 lbs 8 oz and the reset is super short - When shooting quickly, especially when stress is introduced (competition, timer, etc), the gun will periodically bump fire as seen in the video. This condition never happens when shooting slowly and/or when pinning the trigger and so I am convinced it is not a sear issue.

This is obviously not desirable, however the gun builder has inspected it on two occasions and reported back that everything is as it is supposed to be. That said, I purchased a couple 1911 sear springs and increased the trigger pull to 3 lbs, 12 ozs. by bending both the center and left leaves forward a bit further that the original spring. In doing so, the disconnector is significantly "stiffer" and there is a much more well defined click when it resets.

I have not shot the gun a lot since I made the changes, however the changes I made do seem to have corrected the bump fire condition.

My question is this. Can this extra pressure on the disconnector cause a problem for me? Will it harm anything or break?

Magnumite · Mar 18, 2019

The extra pull force on the disconnector won't cause an issue. I would be curious why the bump fire is occurring at the pull weight of 2 pounds 8 ounces on a custom gun. I have had my triggers under two pounds and the hammer didn't bump fire. How much trigger take up do you have? Pretravel present at half cock with trigger held back? Excessive over travel adjusted? It could be hammer hook or sear angle(s). A lighter trigger would certainly help rectify the condition if it isn't a true light weight already. Over zealous recoil spring? Trigger return spring an extra power part?

For what it is worth, virtually all my 1911's are set from the about 3 1/4 to 3 3/4 pounds. Even my pin gun is. Defensive guns go 4 1/4 to 5 pounds. I have one pistol with under 3 pounds of pull force and it runs at 2.5 - 2.75 pounds. I can drop the slide empty and the hammer stays back. Not done out of habit...only to verify all is good after a detail strip and clean. I personally am not fond of real light pulls. I found the pull quality has more to do with how well I shoot the pistol than raw weight of pull.
If you are actually following through on the trigger pull and not releasing it during recoil (yeah, we can do that), AND the extra tension on the sear spring rectifies the condition then I would ask:

- if the sear spring (original especially) was properly adjusted with necessary proportional tension on the respective sear and disconnector leaves, leaves long enough, no frame to spring interference on the left side of the sear spring;
- is the disconnector not binding, nor contacting the magazine in the magwell;
- if all these conditions are not occuring then I would say it is time to revisit the gun smith.

MEGARMS · Mar 18, 2019

Magnumite said:
The extra pull force on the disconnector won't cause an issue. I would be curious why the bump fire is occurring at the pull weight of 2 pounds 8 ounces on a custom gun. I have had my triggers under two pounds and the hammer didn't bump fire. How much trigger take up do you have? Pretravel present at half cock with trigger held back? Excessive over travel adjusted? It could be hammer hook or sear angle(s). A lighter trigger would certainly help rectify the condition if it isn't a true light weight already. Over zealous recoil spring? Trigger return spring an extra power part?

For what it is worth, virtually all my 1911's are set from the about 3 1/4 to 3 3/4 pounds. Even my pin gun is. Defensive guns go 4 1/4 to 5 pounds. I have one pistol with under 3 pounds of pull force and it runs at 2.5 - 2.75 pounds. I can drop the slide empty and the hammer stays back. Not done out of habit...only to verify all is good after a detail strip and clean. I personally am not fond of real light pulls. I found the pull quality has more to do with how well I shoot the pistol than raw weight of pull.
If you are actually following through on the trigger pull and not releasing it during recoil (yeah, we can do that), AND the extra tension on the sear spring rectifies the condition then I would ask:

- if the sear spring (original especially) was properly adjusted with necessary proportional tension on the respective sear and disconnector leaves, leaves long enough, no frame to spring interference on the left side of the sear spring;
- is the disconnector not binding, nor contacting the magazine in the magwell;
- if all these conditions are not occuring then I would say it is time to revisit the gun smith.

How much trigger take up do you have? minimal

Pretravel present at half cock with trigger held back? none

Excessive over travel adjusted? yes

I honestly believe that I am actually following through on the trigger pull and not releasing it during recoil. It is most likely me, not the gun. It seems that increasing the pull has helped me with this, but who knows.

Thanks for the response and putting my mind at ease that increasing the pressure on the center leaf wont have a negative impact on the disconnector.

Magnumite · Mar 20, 2019

If interested Brownells has an article on making a safe 2.5 pound trigger pull written by well know pistolsmith Jack Weigand, going back some years. Here is the link you may find interesting:

https://www.brownells.com/aspx/learn/learndetail.aspx?lid=12535

You may also consider:
The sear fully captured by the original design half cock notch may not have pretravel. To check for half cock pretravel try this:
- Remove mag ensure empty chamber;
- pull and hold trigger back;
- push slide back until sear just engages half cock notch;
- release trigger to verify pretravel. Correct if required.

MEGARMS · Mar 20, 2019

Magnumite said:
If interested Brownells has an article on making a safe 2.5 pound trigger pull written by well know pistolsmith Jack Weigand, going back some years. Here is the link you may find interesting:

https://www.brownells.com/aspx/learn/learndetail.aspx?lid=12535

You may also consider:
The sear fully captured by the original design half cock notch may not have pretravel. To check for half cock pretravel try this:
- Remove mag ensure empty chamber;
- pull and hold trigger back;
- push slide back until sear just engages half cock notch;
- release trigger to verify pretravel. Correct if required.

Thank you. I will check it out.

Correcting a Bump Fire Condition on 2011

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