1911: Can the Sear Break?

[carnaby]

I've been futzing with my Springfield 1911 for a while, and it seems to me that if the sear broke, the hammer would fall and would set off a live round if one were in the chamber.

So, safety of the design depends on the potential for the sear to break. What do more experienced folks have to say about this? What if your part has an internal defect?

Second, the contact area between the sear and the notch on the hammer seems small. Could it slip off some how? Does that area wear down over time and thousands of trigger pulls?

This is probably what people were thinking about when they designed the series 80 and Kimber II pistols. Is this necessary?

 

[YoPedro]

Broken sear

As luck would have it, my sear broke this past Friday at the range. it was my own fault though. The peak of the saddle rolled off. It's what happens when hardened parts wear past the exterior shell and the brittle interior is exposed to external forces. I bought the gun about 13 months ago, and I should have replaced the critcal friction parts.

When the sear broke, the hammer dropped about a half measure, not enough to engage the firing pin. If it would have hit the primer it would not have been a problem though because I was in the firing position hammer down when the break occured.

I disassembled the gun and found the broken part which ended my day at the range. back at the shop I replaced the sear, and as luck would have it, now my trigger feel like a brick sliding on concrete. I guess I need to pay for a trigger job to get back that "glass break" feel.

 

[GreenFurniture]

The first thing to do when you buy a 1911 variant is to check and see if the lockwork are MIM.

If they are then the next thing to do is change them out for tool steel internals.

 

[Onmilo]

The sears on 1911s can and do break.
If the hammer is properly cut and dimensioned, the half cock notch will be large enough to capture the broken edge of the sear and prevent the hammer from fully dropping to engage the firing pin.

With the old, non locking firing pin guns a complete sear failure, such as a large section above the sear pin through hole breaking away, could allow the hammer to fall to the pin and this could cause the gun to fire the chambered cartridge but the diconnecter would still remain engaged to the under side of the slide and the pistol would not continue to run out of battery.

With the new pin lock designs, should the sear fail and the hammer fall to the pin the gun will not fire because the pin locking plunger would remain engaged.

 

[jkr266]

You can buy matched hammer/sear/disconector kits form several manufacturers. ive been using the Cylinder and slide kits to upgrade several of my older 1911s. They give a fantastic trigger pull, and the only fitting that might be required is the safety. Although the three i've doen so far haven't needed any, they were all straight up drop ins.

 

[gc70]

Yes, 1911 sears can break. The lower crossbar of the sear broke on one of my 1911s. The break in the crossbar had no effect on the sear's engagement with the hammer and I did not even know the sear was broken until the next time I detailed stripped the pistol.

 

[IS300_TRD]

I just got a Springfield TRP Operator. How can I tell if lockwork are MIM?

 

[Control]

It is worth noting that when the 1911 thumb safety is on the stud that locks the sear also prevents the hammer from falling. If the gun's safety is on, the sear could effectively vaporize and the gun would not fire.

If the safety is off, and your sear fails, and the half cock notch doesn’t catch the hammer, and your gun is not pointed downrange or at a safe backstop, then you might have a problem. However, I would have to say at that point that it’s simply not your day and if the gun doesn’t get you, lightning will.

The series 80 firing pin design was not added for sear breakage reasons. It was added to keep the inertial firing pin from hitting the primer in case of an accidental drop from a large height to a hard surface on the muzzle or rear of the pistol.

 

[Walkalong]

I just got a Springfield TRP Operator. How can I tell if lockwork are MIM?

They told me they were MIM. I passed on the gun. Not for 1400.

 

[Old Fuff]

One does not have to worry too much about "what if's" on a design that's been in active service for 96 years. If something is a problem it was likely discovered many years ago.

In any case, Tuner did some experiments with a broken sear to see if the hammer would fall with enough impact to set off a primer. It didn't...

It was reported here on The High Road, and a search should turn the thread up.

 

[IS300_TRD]

I didn't get it for 1400. Got it in the group buy for 1000.

 

[Spartacus451]

It is worth noting that when the 1911 thumb safety is on the stud that locks the sear also prevents the hammer from falling. If the gun's safety is on, the sear could effectively vaporize and the gun would not fire.

I respectfully disagree. I believe the hammer would push the safety down out of the way. I believe that Old Fuff or 1911Tuner has mentioned this to be the case before.

 

[Old Fuff]

I respectfully disagree. I believe the hammer would push the safety down out of the way. I believe that Old Fuff or 1911Tuner has mentioned this to be the case before.

The safety lock was not intended to block a falling hammer but it sometimes does - but the hammer can also cam the safety to the "off" position.