I have a 1911 in 45 acp (Springfield Armory) that I have shot for around 20 years. Has always been very reliable. About a year ago had to replace the sear as wear had caused the very nice 3.5 lb. trigger pull to drop to nearly 2 lb, and I don't trust that light a trigger. I installed a Chip McCormick prepped sear to mate with the Titanium hammer, (full .0022 on the hooks) and have a very nice crisp 4 lb trigger. Recently, I noticed that if you squeeze the trigger with the thumb safety on, then drop the safety (finger off trigger) the hammer falls to the half cock notch. The hammer will not fall with the safety on or if the grip safety is not depressed.

I've been through the Kunhausen book and can't seem to find what I need to address to fix this.

Any assistance is appreciated.

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H Richard
SWCA1967 SWHF244

First thought is that you replaced the sear without fitting a new safety, and you have a marginal "short safety" situation.
Drop ins don't. (Murphy corollary #169)

Are you meaning the grip safety where the forward projection on it engages the rear of the sear?

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H Richard
SWCA1967 SWHF244

No, look on pg 91, fig 144 caption, & fig 135 in Kuhnhausen.
Safety stop stud must match sear length and prevent any movement.
Variations in pin alignment may affect "drop in" fit.

I devoutly hope you misplaced your decimal point on sear engagement. Twenty two ten thousandths of an inch isn't sufficient sear engagement. Your issue with the sear/safety is that the new sear rotates deeper into the hammer than the previous one. There's space between the sear leg and the safety lug. I expect you can peen the edge of the safety lug to create a projection that will allow you to properly fit the safety to yout new sear. A dot of weld material in the same place will allow the same, but requires equipment and skill.

22/1000ths. I've determined it needs a new grip safety. Midway needs the money anyway. Gives me a chance to put a new Ed Brown beavertail memory hump safety in. Had to order the frame altering fixture also.

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H Richard
SWCA1967 SWHF244

Your thumb safety needs to be replaced/fit.

To fit the safety, you remove the grip safety, then reassemble the gun complete with slide on frame. Rack slide (hammer back, don't touch trigger) With the thumb safety removed, you can now see how the thumb safety engages with the sear. As you fit the thumb safety (leave spring/plunger off for now) flip it on and off, you can clearly see what the safety turns against. There needs to be .002 or less clearance between safety and sear while safety is on (up position), if not you replace the safety or peen it so it touches the sear while up. I use a strip of paper and slip it under the safety, then flip it on, if it grabs the paper the safety is OK.
If the safety jacks the hammer rearward, you must remove metal with a file on the safety lug and test fit again.
Take your time, it's easy to fit. good luck

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NRA Benefactor Member

Thank you. With the thumb safety on, and the grip safety not depressed, the hammer does not move at all. What is happening is with the thumb safety on, and the grip safety depressed, the hammer will (evidently) move forward a fraction, then when the thumb safety is dropped the hammer falls to half cock. I had thought it was the extension on the grip safety too short. (I've never had much luck peening it in past work, just replace it.) I'll remove the grip safety and test as you described. That sounds like it should be the problem area. This might be a good time to replace all the pins aslo. Gun probably has > 40,000 - 50,000 rounds through it. I've done all the work on this gun over the years, except the machine cuts for the Bomar's and the application of the metaloy finish.

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H Richard
SWCA1967 SWHF244

I had a typo with my post, so make sure you work only with the thumb safety, as the grip safety is not your problem (grip safety is a drop safety).

When looking at the sear (with the grip safety removed) you want zero sear movement as you touch the trigger. If you see sear movement with the safety on, is no good and the safety needs to be fit.

99% of the time you just replace the thumb safety and start over. Some people have a hard time to peen the lug or others have no way to weld or solder it.

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NRA Benefactor Member

Although not a gunsmith, I believe you have a situation where there is slight movement of the sear when the trigger is pulled even when the safety is on. This results in the trigger nearly being released, then when the safety comes off, the hammer falls. I believe you need to have a new slide lock safety fit, and of course, the sear and hammer engagement surfaces should be checked for damage.

Also check that the plunger tube is solid.

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John

For your future endeavors of the 1911 kind there are some very good sites dealing with only the 1911. Not that the help here is not excellent, just that all the stickies, and the entire forum are devoted to 1911s, its uses, maintenance, and alteration.

This is the one I belong to.

This is their home page and is only a knowledge base.

OK Guys,

Let me add one to this:

About every 8000-10,000 rounds I completely disassemble my Springfield IPSC gun. Did so today.

Used my Power Custom stoning fixture to touch up the sear, replaced the main spring, recoil spring, shock buff, etc.

When I got it together, did the usual safety checks, and after pulling the trigger with the safety on, the hammer dropped when the safety was released.

Hit this and a few other forums to find out what I screwed up. Nothing...I'm an experienced "sear toucher-upper", used dycem to check the 60/40 cut.

Here's what I found. When re-assembling the pistol, I got the hammer strut caught under the mainspring housing against the sear spring. (I know -- dumb A**) Used my dental pick to pull it out and then pushed the housing in place and pinned it.

When forced behind the mainspring housing, the strut bowed the disconnector leg of the spring way into the mag well against the back of the trigger bow. The slight rearward movement that the grip safety allows was enough to disengage the sear.

I threw away the sear spring, replaced it with another, and problem solved.

Moral of the story is, no matter how many times you've taken that gun apart --- take you time and put it together carefully.

Hope this helps.

H Richard:

I've always used .020" as a Hook standard as that is what the Jig I use is made to do. Was the sear angle and sharpness check when the hammer was installed? I suspect you might need a new thumb safety as they are also sort of custom fit. Please let us know how you make out.

You do realize this thread is almost 5 years old. H. Richard is still posting, so send him a PM if you think he hasn't got it fixed yet. Ivan

Well I posted this at 5 am and I guess my eyes were half closed because I did NOT realize this thread was so old. I sure hope he fixed it and I will check posting dates a bit closer now. Thanks. A bit embarrassing - but I am human!

SHOULD HAVE HAD MY COFFEE FIRST!

Yes the gun was fixed long ago. I don't recall just what it required back then, but I did replace both hammer and sear and I have put quite a few round through since.

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H Richard
SWCA1967 SWHF244

I knew it was an old thread, but 1911 problems and fixes will always be of interest to someone. A thread like this is a valuable tool.

Hopefully, in another hundred years or so, the 1911 will still be the auto of choice, and gunsmithing tips still valuable.