Hammer To Half-cock

[XRe]

I've heard there's a way to get a 1911 to drop to half cock when manipulating the action by hand, but never stumbled across it before. I'm wondering if I have, or if I've got something wrong w/ the gun??

Here's what I'm doing - gun unloaded, hammer cocked, safety off. Retract slide to rear. Pull trigger to rear. Ease slide forward somewhat quickly, enough to allow some force to close the slide. Hammer is now at half cock. The trigger also moves freely, at this point (ie, it appears that the disconnector is disconnected)- unlike hammer at half cock in the usual fashion, where the disconnecter is engaged, and (depending on the half cock hooks) you can still drop the hammer

If I cock the hammer, pull the trigger (dropping the hammer) and then vigorously actuate the slide (with the trigger pulled, or releasing the trigger) or even slingshot it, the hammer stays cocked. I don't think this is a sear bounce sort of issue, or anything.

Thoughts???

[Radical Precision Designs]

How old is this set-up?

Kindly do thid test. (with an empty gun, no mag in) Cock the hammer completely. ( not just half-cock) Now keeping an eye in the hammer position, slowly rack the slide over it, still watching the hammer for any substantial additional rearward motion as the slide passes over it. Now 'very' slowly allow the slide to return to battery while again watching the hammer, and see how far it moves forward before engaging the sear at full cock. If there is 'extremely' little motion in the hammer as the slide passes over, or no motion at all it will signify that the top area of your hammer has been recuced too much and the slide rearward motion can barely set the hammer over the sear. This is very rare and unusual.

Another exercise is to lock the slide back and check how much further down the hammer is able to travel before it touches the (beavertail cavity) grip safety. If the grip safety is pushed down/in by the hammer as the slide passes over then your hammer spur is too large or not mated to the cavity of the grip safety. Again this is very rare, but has been known to happen on newly fitted 'random' parts.

Other than that, your sear spring (left one) tension might be suspect or otherwise a rounded off sear or hammer hooks.

There of course could be a number of possibilities. But what I don't like and hints of sear engagement wear or timing is that you said you were holding back the trigger as you 'fully'released the slide and then the hammer ended in half cock, even though you say the disconnector was disengaged. I assume you heard the disconnector 'engaging' as you released the trigger?

[XRe]

Hi, Venry - thanks for the response

How old is this set-up?

I don't honestly know - I've got maybe 3K on the gun myself, plus a lot of dryfire, but I bought it used, so.... It's the stock factory STI parts...

If there is 'extremely' little motion in the hammer as the slide passes over, or no motion at all it will signify that the top area of your hammer has been recuced too much and the slide rearward motion can barely set the hammer over the sear. ... If the grip safety is pushed down/in by the hammer as the slide passes over then your hammer spur is too large or not mated to the cavity of the grip safety.

Gun passes both of those tests fine.

Other than that, your sear spring (left one) tension might be suspect or otherwise a rounded off sear or hammer hooks.

Hm. I would've thought that improper sear spring tension would also allow the hammer to drop (fully or to half-cock) if I cock the gun, pull the trigger (and keep it pinned back), and then rack the slide - but I can't seem to get it to half cock that way at all. Or is my thinking flawed, here?

I guess I should also say that the gun has had almost 1000 rounds through it without even disassembling the lower - just field strip and clean the top end and the available areas in the frame. It's possible the spring has "untensioned" itself - but it's at least put together properly

There of course could be a number of possibilities. But what I don't like and hints of sear engagement wear or timing is that you said you were holding back the trigger as you 'fully'released the slide and then the hammer ended in half cock, even though you say the disconnector was disengaged. I assume you heard the disconnector 'engaging' as you released the trigger?

No, I don't hear the disco click when I release the trigger when it's in this half-cock condition. I also don't feel resistance against the sear when I again pull the trigger (as you would expect - the sear would be captured in the half-cock notch). The trigger moves freely, except for the pressure on it by the middle leg of the leaf spring. I guess that's what I'm assuming means the disco is disengaged - it's not inbetween the trigger and sear in this condition, somehow.

Edited November 12, 2005 by XRe

[XRe]

Was lucky enough to be surrounded by gunsmiths at the match today. Apparently, the overtravel adjustment screw had fiddled itself loose. I could swear I was told I had too much overtravel, but in hindsight that doesn't make sense... (I was up way early to go help set up, so... half asleep, at that point). Either way, Dave Cupp kindly adjusted my overtravel, and the gun now works flawlessly!!!

Gotta LocTite that puppy in place, now...

[ima45dv8]

I could swear I was told I had too much overtravel, but in hindsight that doesn't make sense...

Hmmmm, that actually does make sense. Very recently we had a local shooter whose .45 SS was doubling, and it turned out to be the overtravel setscrew had worked loose and was allowing too much movement of the trigger. It went back far enough to interfere with the operation of the disconnector. I think it was holding it (the disconnector) up, but it's late and my recollection of the details could be faulty (like THAT'S never happened before!).

I had never heard of it before, but John Harrison (who you may remember form your days in the Atlanta area) was the one to find the problem. A quick adjustment of the overtravel screw cured the problem.

...Mark

[XRe]

I had never heard of it before, but John Harrison (who you may remember form your days in the Atlanta area) was the one to find the problem. A quick adjustment of the overtravel screw cured the problem.

John is a sharp man - and also a lurker on these forums

[Radical Precision Designs]

There is a sweet/sour spot in the trigger adjustment screw and take up tabs.

As you know if you tighten the adjustment screw too much, the rear motion is not enough to release the sear. Sometimes this becomes a sour spot as it will not release the sear. Other times it will affect a "marginally worn/fitted" disconnector's "timing", disengaging properly, 'forcing the sear to "capture" the hammer in its "monitored" descent.' But usually this happens when you "tighten" the screw too much to remove trigger travel, not when it's loose as would be the case with "all non-adjustable" triggers. Many of the "full-unintended-auto" malfunctions have been attributed by marginally set adjustments screws.

You will notice that from factory, most if not all adjustable triggers come "unadjusted" and with plenty of travel to spare. I have a feeling that some "lawyer" advised them to do it that way for liability issues.

The "take-up" tabs, should also be carefully adjusted to allow "some" travel before engagement. "Zero-travel" adjustment should be left to a very competent gunsmith, as it usually requires very close fitting and some times alteration of the disconnector tunnel or the disconnector itself. Over-adjusting the "tabs" will cause the disconnector not to re-connect as the trigger is released after a firing cycle, giving the same result as if you did not release the trigger.

Monitor those adjustments religiously, and "indeed" apply blue-loctite to that trigger set screw. Although unusual for a set-screw to tighten itself, it has been known to happen often enough. (Very often is an over-zealous shooter wanting to remove all the "creep" from the trigger.)

Normally at the other end, as when there is "no trigger adjustment screw" the grip safety contains a trigger "bow" stop contact point which should stop the bow from "over-pushing" the sear, which frankly can be made redundant if the disconnector is working/disengaging properly.

With a "high wear" competition gun it's a good idea to periodically check and replace the disconnector, since they do sustain "rub" wear continually.

Edited November 14, 2005 by Radical Precision Designs