1911 Half Cock Discharge... Help!

[Duelist]

I recently finished my first 1911 build, basically modernizing a Colt Combat Commander with a Duracoat paint job, beavertail safety, enlarged thumb safety, flat MSH, and a medium length trigger. I kept the original Colt Hammer, Sear and disconnector. After test firing several hundred rounds without fail, the hammer will fall from half cock when the trigger is pulled and grip safety depressed. What could this problem be? Could it merely be a worn sear and disconnector or is this an indicator of a deeper problem? Please help, I'm new to the whole gunsmithing thing

 

[CAWalter]

The Series 80 hammers do not have a captive half cock. If you have a Series 70 style captive half cock hammer and it drops with a trigger pull the pre-travel is insufficient to fully engage.

CAW

 

[average_shooter]

Some hammers have a half-cock "shelf" instead of a full hook that captures the sear. Your hammer could either be designed like this or the hook may have worn or broken off. You'll have to pull it apart and take a really close look at the mating surfaces to figure it out.

My SA 1911 has a hammer with the shelf-style half-cock notch and if enough force is applied to the trigger the hammer will fall from half-cock.

 

[Got_Lead?]

I have a Springfield Mil Spec that can do the same. I've never thought too much about it. If it bothered me, I'd undercut the safety sear a bit.

 

[Duelist]

This is a Series 70 gun.

@CAWalter: That would mean I have to back out the trigger adjustment screw?

 

[CAWalter]

This is a Series 70 gun.

@CAWalter: That would mean I have to back out the trigger adjustment screw?

No, the screw in the trigger is for over travel. Pre-travel requires the bow go further forward, or the disconnector ears can be thinned to the minimum of .030", and then the sear legs can be thinned to provide the needed pre-travel. Check by pulling to half cock and feeling the trigger, there should be a slight front to back play, which indicates enough pre-travel. Yours if not fully engaging will feel tight.

CAW

 

[David E]

Sounds like the quarter cock safety shelf is working as designed.

1/2 cock was never intended to be a true safety per se. It was/is intended to catch the hammer should it slip off the full cock notch.

But the 1/2 cock didn't drop the hammer when the trigger was pulled, so folks mistakenly thought it was an actual safety. (it's more dangerous to carry it on 1/2 cock than full)

So designers decided to create the 1/4 cock stop / shelf instead. Making it so the hammer fell if the trigger was pulled confirmed that it was not a safety proper, but the safety feature it was originally intended to be.

With the original 1/2 cock, it's possible to perch the point of the notch on the edge of the sear. A jostle or slight touch of the trigger and the hammer falls, possibly with enough momentum to fire a round

Since the new design is only 1/4 cock, there is not enough momentum developed to fire a chambered round.

.

 

[1911Tuner]

If the hammer has a true captive half-cock, there shouldn't be much, if any front to back play in the trigger when the hammer is in that position. The trigger should be solidly locked with barely discernible movement.

Duelist...Are you sure that the gun has the original hammer? Might be a good time to pull it out and look at it. A quick test to see if it's a Series 80 hammer is to note how far the hammer is from the slide when in the half-cock position. A Series 80 hammer will sit very close...at quarter-cocked.

The trigger's length could keep the sear from falling completely into the notch when manually cocking...but it would have to be far too long. Disassemble the frame and see how far the trigger stirrup protrudes past the rear panel in the frame. It should sit flush, or nearly so.

David E...The half-cock most assuredly is a safety position. Browning refers to it as such right there in the 1910 patents...interestingly enough while giving instruction on lowering the hammer to half-0cock with one hand...neatly debunking two popular myths in one paragraph. Go look.

Think about what happens with a captive half-cock notch. Hammer and sear are interlocked. Even the trigger is frozen in place. The whole fire control group is locked up and disabled. If that doesn't meet the criteria for a safety, I'd like to know what does.

For the record...There's no such thing as a Series 70 Commander/Combat Commander. COlt never built such a critter.

 

[David E]

I did not see where JMB called the 1/2 cock notch specifically as the "safety position."

He did say "lower the hammer to the safety position," but nowhere does he specify that to be the 1/2 cock notch.

He also speaks of the mag release doubling as a magazine disconnect safety which didn't apparently get included in the final, final design.

He also makes clear that some features are not limited to the 1911, thereby getting a two-fer at the patent office.

Regardless, I stand by the mechanics in my previous post.

 

[CAWalter]

When the hammer is in half/quarter/safety cock whether with a captive or not the trigger is limited in travel front to back. Front the same as not and to the back limited by the sear's position as the tip is arced deeper than at full cock. If the trigger is absolutely tight this is an indication that the sear tip can not fully engage the notch to it's full depth.This is due to the sear arcing into the notch as far as it can, but stopped before full engagement by the lower legs contacting the disconnector against the back of the bow.

This condition then can cause the sear nose to just catch a captive notch and not seat into it allowing the trigger to be pulled and hammer to drop. If more pre-travel is added to this system then the sear can fully engage.

CAW

 

[1911Tuner]

1. "I did not see where JMB called the 1/2 cock notch specifically as the "safety position."

It's there. Keep lookin'.



2. "He did say "lower the hammer to the safety position," but nowhere does he specify that to be the 1/2 cock notch."

It states:

"To lower the hammer to the safety position without touching the firing pin."

Since the only place the hammer touches the firing pin is full down, that only leaves the half-cock position.

Note that I'm not advising you to use it as a safe carry mode. Only alluding to Browning's intent. It is a de facto safety.

3. When the hammer is in half/quarter/safety cock whether with a captive or not the trigger is limited in travel front to back.

In my experience, when the sear is captive in an original design half cock notch, the trigger is securely frozen in place with, at most, barely detectable front to rear movement...and only if manipulated with some force.

All my pistols, save the two Colt 1991A1s that I use for beaters...numbering nearly 4 dozen...have captive half cock notches on the hammers. Only one lets the trigger move front to rear by more than about the thickness of a sheet of paper. One bone stock Norinco gives up about a 64th inch of travel...and the trigger in that one sits about that far below flush with the rear frame wall.

My first suggestion to the OP is to determine which hammer is in his gun. Unless he bought it spankin' new, there's a chance that somebody swapped it out for a Series 80 hammer. If it's original or correct, either the half cock notch has been damaged or modified, or something is keeping the sear from fully resetting and it's staging on the edge...which is unlikely because if the sear won't reset sufficiently to grab the half-cock...it probably won't engage the hooks and hold at full cock.

 

[CAWalter]

This was originally asked and information for both hammer styles given, he, the OP, stated it is a Series 70 hammer.

While many factory and other assembled 1911 will not allow the sear to fully engage the half cock due to insufficient pre-travel to do so, suffer no other consequences from this. However it can and does stop a captive notch from being captive.

Personally I set the pre-travel so when the trigger is held back and the slide forced back just enough for the hammer to engage the half cock and release the slide back to battery, the trigger must re-set when released. Many won't.

CAW

 

[1911Tuner]

1. "This was originally asked and information for both hammer styles given, he, the OP, stated it is a Series 70 hammer."

He did...but until we know that:
A. It is, in fact, the original hammer, and if not that:
B. He recognizes the difference between the two different hammers...we have to ask.

2. "While many factory and other assembled 1911 will not allow the sear to fully engage the half cock due to insufficient pre-travel to do so..."

If the sear can't move far enough to enter the captive notch...from whatever problem is keeping it from moving or resetting...it can't move far enough for the hooks to grab it, either.

We can sit here and guess and argue the points until cows fly...but the thing for the OP to do is first determine exactly which hammer he is working with, and...if it is, in fact an original hammer and not a Series 80 type...assemble the gun without the grip safety so he can see exactly what's going on in there.

If he finds that it's a Series 80 hammer, we can tell him that the hammer falling from the quarter-cock shelf is normal and nothing to be concerned with.

 

[CAWalter]

Not quite true, insufficient pre-travel for the half cock can still provide plenty of pre-travel for the sear to fully engage the hammer hooks. Why, because the hammer hooks and depth are not the same as the half cock. This is why when setting the over-travel screw checking to make sure the sear nose is forward enough to clear the half cock. Pretty rare to ever be the opposite. You mentioned your triggers are pretty tight when in half cock, correct, because the half cock notch is also deeper than the full cock and require more pre-travel to fully engage. There you go.

CAW

 

[David E]

2. "He did say "lower the hammer to the safety position," but nowhere does he specify that to be the 1/2 cock notch."

It states:

"To lower the hammer to the safety position without touching the firing pin."
.

That statement is specifically referencing previous designs, not necessarily the 1911. Read it closely.

While he may have meant what you assert, it's not the slam dunk you allege.

Further, it still does not affect the mechanics described in my first post.

 

[Old Fuff]

Browning's earlier .38 and .45 pistols did not have safety locks (manual safties) and the half-cock notch was considered to be a safety position, as for an example, like Winchester lever action rifles made during that period.

"To lower the hammer to the safety position without touching the firing pin."

If you lower the hammer in a manner that it doesn't touch the firing pin, the only way to do it is to lower the hammer into the half-cock position.

Keep in mind that the prototype pistols that became the model 1911 didn't have a safety lock until late 1910. Browning didn't like the idea, but the Army insisted.

 

[1911Tuner]

1. "That statement is specifically referencing previous designs, not necessarily the 1911. Read it closely."

The statement in the patent is specifically referring to the 1910 model, which...after adding the manual safety at the US Cavalry's request...became the 1911.

2. "While he may have meant what you assert, it's not the slam dunk you allege."

If he meant for the half-cock to be a safety...and referred to it as such...there really isn't a point to argue. It's a safety....by design and intent. All I did was present the facts. What you do with that is up to you.

3. "Further, it still does not affect the mechanics described in my first post."

You brought it up.

Back to the original question.

First we have to find out if the hammer is the original or a Series 80. At this point, we're not sure, and we don't even know that the OP knows the difference. Then we can proceed with the diagnosis. Until we have that information, we're spinning our wheels and wasting bandwidth.

 

[Duelist]

As far as I know, the hammer is original, and the Commander was manufactured in 1972. Upon inspection earlier today, the Nighthawk trigger protrudes slightly further than the edge of the trigger channel. How do I remedy this? I am leery of removing metal from the disconnector.

 

[earplug]

Lack of trigger slack

I just had the same experience on my Springfield 1911. I changed triggers from a unknown medium to a shorter Cylinder and Slide.
The new trigger bow was to long and it would not allow enough trigger take-up slack when the trigger was operated. Gun would double.
I ended up using the old trigger after I filed off materiel from the front to make it shorter for my finger to reach.
I have had other supposedly drop in parts not work as dropped in with this pistol.
I won't blame the after market or Springfield as I don't have the Colt blueprints or the tools to measure most of them.

 

[rondog]

I vote for taking it to a competent 1911 gunsmith, just to be safe.

 

[David E]

He said: "heretofore in pistols of this class....."

Note the plural "pistols."

How you get from that he was only talking about the model 1910 is interesting.

Still, I agree he was probably referring to the 1/2 cock notch. It may have been in vogue at the time, but it doesn't mean it was then or is now the best idea, mainly for the reasons I stated.

I find it very interesting that he apparently fashioned the tang of the grip safety and hammer spur to allow the one handed hammer lowering, not to make it more comfortable to shoot!

To the OP: Take it to a gunsmith. No reason to take metal off the disconnector!!

 

[1911Tuner]

1. . Upon inspection earlier today, the Nighthawk trigger protrudes slightly further than the edge of the trigger channel. How do I remedy this?

By trying a different trigger.

"I am leery of removing metal from the disconnector."

Before you do that, try a different trigger. The point is probably moot, though. As long as the sear resets with the trigger in its static position, the hammer shouldn't fall from pulling the trigger if the hammer has a captive half-cock notch. From a Series 80 quarter-cock shelf...it's normal.

3. "As far as I know, the hammer is original."

And this is the meat of the matter.

Do you know how to spot the difference between a Series 80 and a pre-80 hammer?

Did you buy the gun new or used? If used...it could have been changed. If new, it could have been altered or damaged. These are things we have to know before we can proceed. A picture o the hammer would be helpful.

4. " How you get from that he was only talking about the model 1910 is interesting."

The patent's March 1910 date kinda gives it away. "Pistols in its class" is referring to the grip safety and hammer redesign that allows the firer to disengage the grip safety with one hand by pulling the hammer past full cock and bearing on the top of the GS tang. A plus for mounted troops who have the other hand wrapped up in a rein. One hand manipulation wasn't possible with the 1909 Model.

 

[Duelist]

I didn't know there was a difference between series 70 and 80 hammers. I bought the gun used. At half cock, the hammer sits further back from the slide than my Kimber. What about trying different disconnectors?

 

[1911Tuner]

Try somethin' for me, just for giggles.

Half-cock the hammer, and push forward on it firmly. Pull the trigger. Does it still fall to the firing pin?

We really need to know if this hammer has a captive half cock notch, or a flat shelf.
Or...If the captive half cock notch has been damaged or altered. A picture of the hammer...taken from the side...would really help.

Just to clarify, there is no such thing as a "Series 70" hammer. There are Series 80 hammers...with a quarter-cock shelf...and all others with a half-cock notch. Recently, Springfield has been using a hammer with a quarter cock shelf and a true half cock notch. Why remains a mystery. I'm not sure if Kimber has followed suit on that particular modification, but anything is possible.

Forget the disconnect for the present. If the hammer will hold full cock, the sear is resetting correctly, and it therefore should engage the half-cock unless the notch is too narrow for the sear to interlock itself into it.

 

[Jim Watson]

A picture of the hammer out of the gun would be a big help in diagnosing the problem.
Not as much fun as Internet Twenty Questions, though.