Been a while since I was on the forum last time. Then I wrote about my problem with getting my new thumb safety to engage, after some trigger creep moved the sear out of position and the sear spring did not return the sear.
Well after this I tried to get a better trigger pull so that the sear would not creep. I had my friend that has helped me in fitting parts before and has himself built a 1911 before work on the parts. He filed on the sear and hammer, in hindsight something went wrong. After some 60 rounds my pistol fired a few round full auto, a scary experience. After many tries to fix this with changing springs mainly the sear spring without success I bought a Ed Brown sear, hammer and disconnector.
I dropped them in full knowing that some fitting might be needed , but as two of my friends had had success in dropping in Wilson parts I wanted to try my luck. I was a happy camper for some 200 rounds when everything worked again. But suddenly again the hammer started following luckily no full auto occurred.
I took the gun apart and examined the parts what I found out that the sears main contact surface with the hammer had been beaten into a uneven round shape. I also noticed that the Ed Brown sear was out of spec to long if comparing with the US ordnance blueprints I found from the net by some 0.01 inch.
So what I am getting at is, could this extra length on the sear be the reason that it was beaten up and started causing hammer following. Since then I got a old used Springfield sear from a friend that was much shorter and since then I haw had no problems with the gun.
What are the make and model of this gun?
What is the trigger pull weight on this gun?
The sear nose damage was probably the result of the hammer following, not the cause. If the sear repeatedly drops to the half cock notch, it can damage the nose of the sear.
I'm curious to know if the sear was so long that it held the hammer below the disconnector rail when the slide was back. If so, that means the hammer is falling onto the sear rather than striking the rail and being lowered onto the sear when the slide goes forward.
The gun is a COLT Mk IV series 80, a 1991 if I have it right from 1994. I don't have a gauge to measure the trigger pull so I can only say it is light and quite crisp, but nothing like the one it hade when it was hammer following after the first modification I mentioned. Then it could be described as to been so light it slipped off. Now you now that you are pulling the trigger. Maybe 3+ pounds.
About the hammer follow causing the damage. The Ed Brown hammer has a central secondary hook so when the damage (roundness) is on the whole width of the sear, what does that say?
The diameter of the sear was 0,781 inches, sadly I have not left the measurements from the center of the sear pin hole to the sear contact surface, but it was 0.01+ inches over the .4045-.004 mentioned in the blueprints. But I remember that when I put I side by side on the sear pin with tree others sears that where working fine in other 1911s. It was clearly longer than the rest.
RobL would you mind the process you mentioned as that was new to me. I thought the hammer is all the time controlled by the slide until it is engaged again by the sear . And thus can't beat the sear. Do you mean there is some free space when the hammer is punched back by the slide and then when it recoils back its primary hooks hits the sear before its movement is stopped by the the disconnector rail.
This could be it as there where different marks in the center of the sear surface from the secondary hook, probably from the hammer following.
Quote:
I thought the hammer is all the time controlled by the slide until it is
engaged again by the sear. And thus can't beat the sear
That's how it is supposed to work.
Quote:
Do you mean there is some free space when the hammer is punched back by the
slide and then when it recoils back its primary hooks hits the sear before its
movement is stopped by the the discorail.
That's what I mean. I don't know if your sear is long enough for that, but if it was, it might beat up the sear nose.
It appears that both you and your friend ignore Rule #1 of the 1911 parts world:
There are no drop-in parts in the 1911 world.
Every single part has to be properly fitted in the pistol and of course the fire control parts, sear/hammer/disconnector are always to be fitted to the pistol in hand.