1911 Half Cock Discharge... Help!

[SSN Vet]

both of my Ed Browns (built by Ed Brown or his elves) that I've done absolutely nothing to perform in exactly the same way, so that's why I asked if the lack of pre-travel has anything to do with the design of the Ed Brown hammer

my bad... I didn't read / remember well... I just recently purchased EB parts and was thinking you did likewise as an upgrade.

 

[macadore]

With the original 1/2 cock, it's possible to perch the point of the notch on the edge of the sear. A jostle or slight touch of the trigger and the hammer falls, possibly with enough momentum to fire a round

Can't emphasize this enough. A Series 70 on half cock is an AD waiting to happen.

 

[CAWalter]

Can't emphasize this enough. A Series 70 on half cock is an AD waiting to happen.

Possibly. The cure is more pre-travel to allow the sear nose to fully engage.

CAW

 

[Duelist]

Well, after disassembling the Commander and reassembling with two different triggers, I have determined that the lack of pre travel is caused by the Nighthawk custom trigger stirrup being out of spec. A trigger from my Kimber and a trigger borrowed from a friend both fit, and allowed sufficient pretravel that the Commander passed the half-cock test. I will be sourcing another trigger soon.

 

[SSN Vet]

Nighthawk custom trigger stirrup being out of spec.

I'm not sure you can say that because it doesn't fit your frame and mate with your ignition parts, that it is out of spec.

For all the CNC precission that modern manufacturing processes bring, different manufacturers make frames and ignition parts with variation in their design. Each one likely sees theirs as an improvement.

This does highlight why many 1911 smiths prefer to work on Colt frames, however. Some even refuse to work on certain manufacturers frames.

Can't make a living if the parts you order don't fit right and you have to try several variations to get correct fitting parts.

 

[CAWalter]

If the bow is in spec. it will be 1.655"-.005". this is the dimension from the inside of the back at the top to the center point of the bow arc at the front, inside.

CAW

 

[MCMXI]

I installed the sear from the Valor (0.0840" sear legs) in my Kimber that has an Ed Brown hammer and sear (0.0915" sear legs) and the trigger had a very small amount of movement with the hammer at half cock i.e. with Ed Brown hammer and Valor sear. However, the trigger wouldn't reset when released following the test described by CAWalter ....

"when the trigger is held back and the slide forced back just enough for the hammer to engage the half cock and release the slide back to battery" the trigger must re-set when released."

I used a small file and some emery paper to reduce the thickness of the EB sear legs (where they contact the disconnector) to 0.0800" and now the trigger has a little movement at half cock AND it passes the reset test!! This Kimber is my USPSA match gun so I'll shoot a few matches to see if it holds up without any problems and then consider doing the same thing to both of my Ed Browns and another Kimber.

This thread has really helped my understanding of the 1911 trigger group. I can follow the logic behind having a tiny amount of play in the trigger at half cock. If there's play, then the sear is fully engaged in the half cock notch. If there isn't any play, the sear may be 20%, 30% .... 90%, 100% engaged but there isn't any way to know for sure. Sufficient pre-travel and the resulting play in the trigger at half cock removes all doubt. I like it!! If it helps to reduce the chance of trigger bounce and/or hammer follow then I like it even more.

Thanks to the OP for starting the thread and to 1911Tuner and CAWalter for sharing their knowledge.

 

[CAWalter]

1858, your following the back, and forth and getting the point is reassuring, and validating of your interest in better understanding the nuances of the 1911, with it's simple, but complicated operation.

CAW

 

[SSN Vet]

Personally I set the pre-travel so when the trigger is held back and the slide forced back just enough for the hammer to engage the half cock and release the slide back to battery, the trigger must re-set when released. Many won't.
CAW

Just tested my S80 Commander (non-captive quarter cock) and the trigger resets.

What's even more amazing is that I think I understand why

Great thread!

Thanks to all

 

[SSN Vet]

So here's a related question....

When the trigger resets, what makes the "click" noise?

Is it the disconnector ball hitting the top of the arced recess in the slide?

Or...

Does the paddle at the bottom of the disconnector catch on the bottom of the sear legs, and then snap by them as the trigger is released and the middle leaf of the sear spring pushes the disconnector forward and up?

Inquiring minds want to know!

 

[CAWalter]

Yes that's it, remove the grip safety and watch as you go through the reset and see it.

CAW