Sudden hammer follow on 1911

[bp78]

On stage 1 of a match today, I had a single instance of the hammer following the slide down (a 12rd stage). Stage 2 started and my STI Trojan was then rendered a single shot with the hammer following the slide down on every round. This is a near stock STI Trojan I bought just over a year ago from Brazos. I changed out the trigger (to a long aluminum solid trigger), recoil spring, and some other parts but haven't touched the fire-control parts any. No part changes or issues within the last 1000 rounds either.

I completely broke down and cleaned the internals but the problem persists. I drop the hammer, keep the trigger depressed, and rack the slide, the hammer then follows down completely (IT DIDN'T catch the half-cock catch). The primers on stage 2 weren't even dented, no F/A incident. I borrowed a gun to finish out the match (thanks boo radley).

I don't see the sear or hammer chipped at all or any other obvious failure. Any ideas of what to check or is it just time for a new fire-control set of parts for this Trojan? It's a bit over a year old and has close to 10k rounds on it.

Edited to clarify some vague statements..

Edited April 6, 2008 by bp78

[Steve J]

You say you changed out the trigger. Was the gun set up with a light trigger pull weight? Did you put in a heavier trigger? The heavier trigger could provide enough bounce to dislodge the sear.

Replace the original trigger and see if the problem goes away or remains.

Next. Make the left leaf of the sear spring a little heavier. It will make the trigger pull slightly heavier, but if the sear spring being too light is to blame it will fix it. If the problem returns after a while the sear spring needs to be replaced.

Also you might replace the mainspring with one that is no less than 19#.

Trouble shoot it. See if you can identify the problem, or... just send it back to Brazos Custom for a fix.

Good luck.

Edited April 6, 2008 by Steve J

[Brazos Custom]

First thing I would check is to make sure the sear spring is in properly. It sounds like when you put it together the left leg of the spring is off the sear. You can take the thumb safety and grip safety off and see if the sear spring is in the right spot. It is real easy to get it back together with that leg of the spring off the sear. If that does not work give me a call.

[bp78]

Thanks Steve. The hammer does have a 1/2 cock notch, I just meant to say that the hammer followed down completely, doesn't stop on the half-cock notch. This is a new problem, the trigger, although a little heavier, has been running w/o any issues for 2000 rds or more. I'll try the sear spring bend tomorrow.

It hadn't been disassmbled since the last match it ran fine in a week ago, and after reassembling today it still had the same problem. I'll look at it assembled.

Thanks again Steve & Brazos. Just to clarify, this is a stock STI trigger & not Brazos work.

Edited April 6, 2008 by bp78

[HSMITH]

Sounds like the disconnector is stuck down.

[bp78]

I replaced the sear spring with a Clark 4 leg spring and the hammer follow problems went away for about ~140 rounds. Then, in a local match of course, the pistol again became a single shot with the hammer following down on every round.

After that incident, I replaced everything. A new Extreme Engineering hammer, sear, disconnecter kit, new strut, new ed brown 3-leg sear spring. With the new kit in place yesterday, all dry firing testing was successful as far as I could tell. I took it out to the range and after about 20 rounds it doubled once and then the hammer started following repeatedly. (I was cautious only loading 2 or 3 rounds at a time).

Pulling it apart again, comparing it to my untouched and working NHC pistol, I don't see any problems in the sear spring contacts. I still believe I may not be tensioning the legs correctly and have been hard-pressed to find clear directions on setting up a sear spring properly. The other issue just noticed last night is that the trigger over travel screw had backed out allowing for excessive over travel. Could that be contributing to these problems?

Thanks.

[HSMITH]

Your disconnector is not resetting.

[bp78]

Your disconnector is not resetting.

During the test yesterday, I had plenty of pressure on the disconnector and believe it was resetting. Assembled, pushing on the disconnector showed no movement impediment and it was a bit more heavily sprung than my other 1911s. I'll test it again this afternoon (I bent the left leg to put more pressure on the sear) and watch the disconnector closely. Thanks.

[wide45]

Your disconnector is not resetting.

If the disconector stays down, the sear will still catch the hammer, but the trigger does not reset.

The sear is not resetting. Short disconector?

How old is the STI frame?

[HSMITH]

Pull the trigger and then try to cock the hammer without depressing the disconnector.

[NCShooter]

Pull the trigger and then try to cock the hammer without depressing the disconnector.

I have almost exactly the same problem. Stock STI Trojan (fire control group anyway), about 1000 rounds and all of a sudden the hammer wants to follow.

What will make the disconnect not reset??? Would more tension on the disconnect leg of the spring be a fix?

[bp78]

Pull the trigger and then try to cock the hammer without depressing the disconnector.

Trigger pulled in, I can not cock the hammer manually.

Another match tonight, I ran 15 rounds before the match started no issues what so ever. Stage 1, beep, boom, half-cock notch. Rack, repeat.

Back to the backup gun to finish the match.

I pulled the grip safety off before the match and had another shooter who builds his own 2011s take a look at the sear spring and movement of the disconnector. I nor he believes it's a lack of tension on disconnector (but what do I know at this point).

The trigger is a solid aluminum long trigger, could the heavier trigger be causing the hammer follow to half-cock? I only suggest this because it's a bit heavier than most and the problems surface when I shoot a match and slap the trigger instead of the slow & deliberate paper-punching test cycles on the range.

Edited April 23, 2008 by bp78

[HSMITH]

Wait a minute cowboy, if the hammer is falling to half cock that is a different animal than hammer follow. Follow to me is down all the way.

You need to get this gun in the hands of a pro. It needs to go back to STI or see a real 1911 plumber for a trigger job. It isn't going to get any better. If the hammer is falling to half cock you more than likely have geometry problems between the hammer and sear.

[ajg308]

On stage 1 of a match today, I had a single instance of the hammer following the slide down (a 12rd stage). Stage 2 started and my STI Trojan was then rendered a single shot with the hammer following the slide down on every round. This is a near stock STI Trojan I bought just over a year ago from Brazos. I changed out the trigger (to a long aluminum solid trigger), recoil spring, and some other parts but haven't touched the fire-control parts any. No part changes or issues within the last 1000 rounds either.

I completely broke down and cleaned the internals but the problem persists. I drop the hammer, keep the trigger depressed, and rack the slide, the hammer then follows down completely (IT DIDN'T catch the half-cock catch). The primers on stage 2 weren't even dented, no F/A incident. I borrowed a gun to finish out the match (thanks boo radley).

I don't see the sear or hammer chipped at all or any other obvious failure. Any ideas of what to check or is it just time for a new fire-control set of parts for this Trojan? It's a bit over a year old and has close to 10k rounds on it.

Edited to clarify some vague statements..

deleted due to redundancy

Edited April 23, 2008 by ajg308

[bp78]

1. On closer inspection, the replacement trigger was twice as heavy as the OEM one. 135gr compared to the stock STI plastic trigger at 58.3gr.

(although it ran fine 2000+ rounds after being added)

2. After the latest incident at out Tuesday Night Match, I found that the trigger stop screw again backed out completely.

Could either be attributed to the hammer following or returning to half-cock?

Either way, I've returned the gun back to completely stock. Sear, disconnector, sear spring, hammer, trigger, and mag release. I'll try another range trip, slapping the trigger this time, and see if the problem persists. I also emailed STI to see if they have anything to suggest or if they would like me to send it in.