Can the sear fail? [Archive] - Glock Talk

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xtreme99
03-10-2011, 17:26
Just curious...

I was looking at this picture:

http://www.fototime.com/%7B88EB8B7A-880F-4056-B21F-D5633B3B0239%7D/picture.JPG

And from what I can tell, even with both safeties engaged, and depending on the trigger job on the gun, it is theoretically possible for the sear to wear down over time and cause the hammer to drop unexpectedly, even with both safeties engaged.

Am I wrong in my thinking? It's never been something that worried me, however I would like to know if I'm correct or not.

Thanks!

20South
03-10-2011, 17:41
1911Tuner has posted some good info in the thread below along about page 3.

http://www.glocktalk.com/forums/showthread.php?t=1323164

xtreme99
03-10-2011, 18:02
I passed that thread a while back and meant to look at it but didn't. Found my answer, thanks!

mrsurfboard
03-10-2011, 21:31
1911Tuner has posted some good info in the thread below along about page 3.

http://www.glocktalk.com/forums/showthread.php?t=1323164

Went back and read that entire thread. Very enlightening. Taught me a few things I didn't know about my 1911.

MajorD
03-11-2011, 09:11
it was relatively common that sear wear on heavily used bullseye guns in the old days would get to the point where the gun could go full auto- I have seen it happen a couple times so yes sear wear can cause unintended consequences. It is common at bullseye matches to see shooters holding the hammer back with a thumb while releasing a slide supposedly to limit sear wear but I have never bothered with this technique- again we are talking striclty bullseye guns highly tuned with usually very light triggers.

1911Tuner
03-11-2011, 15:41
Highly unlikely that the sear would fail to the point that it would release the hammer spontaneously while in the holster. Even if it did, assuming that everything else is operating correctly, the half-cock notch will grab the sear and stop the hammer...even with a good portion of the sear nose broken off.

cscprez
03-12-2011, 20:21
A hammer can definitely drop with both the thumb safety and grip safety engaged. Sear engagement surfaces less than .020" and/or hammer shelf angle of greater than 90 degrees and shorter than .018" combined with lightened sear spring can cause hammers to follow the slide forward. I have seen many home grown "trigger jobs" do this. Without jigs and flat stones with sharp, square edges and a thorough understanding of what you are doing can be tragic. A 30X magnifier should be used for checking, along with a set of external hammer and sear pins for checking. Unless the shelf height, squareness, sear engagement surface and "breakaway" angles are all precisely done, you will end up with (1) a trigger job that won't last, or (2) a dangerous condition, or (3) a heavy, gritty pull. I have seen a gun where the sear tip was "polished" on a muslin buffing wheel, then installed. The hammer would follow every third or fourth slide closure. When this happens, the safety notch in the hammer catches the sear nose, eventually either breaking the lip of the notch or the sear nose. Either condition is not acceptable. A clean, crisp pull of 4 pounds (consistent) is all that is needed for a bullseye gun. Remember, NRA sanctioned matches require four pounds, weighed.

20South
03-12-2011, 20:26
A hammer can definitely drop with both the thumb safety and grip safety engaged. Sear engagement surfaces less than .020" and/or hammer shelf angle of greater than 90 degrees and shorter than .018" combined with lightened sear spring can cause hammers to follow the slide forward. I have seen many home grown "trigger jobs" do this. Without jigs and flat stones with sharp, square edges and a thorough understanding of what you are doing can be tragic. A 30X magnifier should be used for checking, along with a set of external hammer and sear pins for checking. Unless the shelf height, squareness, sear engagement surface and "breakaway" angles are all precisely done, you will end up with (1) a trigger job that won't last, or (2) a dangerous condition, or (3) a heavy, gritty pull. I have seen a gun where the sear tip was "polished" on a muslin buffing wheel, then installed. The hammer would follow every third or fourth slide closure. When this happens, the safety notch in the hammer catches the sear nose, eventually either breaking the lip of the notch or the sear nose. Either condition is not acceptable. A clean, crisp pull of 4 pounds (consistent) is all that is needed for a bullseye gun. Remember, NRA sanctioned matches require four pounds, weighed.

Thats a heck of a post for numero uno. Welcome to GT!