Odd 1911 issue, falling to half cock on trigger pull (not following)

[wash]

The issue I'm seeing isn't mentioned in the Kunhansen books and most similar sounding issues are sear bounce which isn't happening here.

I first saw this dry firing a 1911 after swapping out the sear, hammer and trigger.

I'll cock the hammer by thumb or by racking the slide and it will catch in the proper full cock notch, then when I pull the trigger the hammer falls to the half cock rather than all the way to the firing pin.

I first noticed after dry firing several times and saw that the hammer had not fallen all the way. I don't know how many times it did that but it was probably in the dozens. I tried a few more times to see if I could identify the problem and then the tip of the sear (EGW) broke off. I'm sure it was due to battering and not the sear's fault unless it was causing the drop to half cock.

After replacing the sear (I'm trying an STI this time), the same symptom has presented but I've been supporting the hammer so it doesn't fall with full force and speed.

I do have a trigger with an overtravel screw but it is adjusted to allow at least 0.050" of travel after the trigger breaks.

I got my hammer used but it looked ok. I hope the full cock hooks are not screwed up because the trigger felt nice with both sears right out of the box, no stoning done by me.

The sear spring is a Nowlin or some other name brand. I bought it several years ago, installed it, then took it out and it's been sitting. Shot count zero, it's not exactly new but I haven't bent any leaves or anything.

The disconnector is probably MIM but I don't think it's causing the problem.

I don't think the hammer will follow but I haven't tried to shoot it this way.

If anyone has an idea of what to look for, let me know.

[JTROKS]

Sounds like the hammer hooks are short or way off specs. Can't really tell unless we look at the hammer and sear relation with some extended pins mounted on your frame.

[redcliff]

Hard to diagnose without examining everything. I'd suggest adjusting your over-travel screw to 1/2 to 1 turn out from where the sear clears the half-cock notch; you can drop the main spring housing, remove the hammer strut from it for easier checking, then slide the msh back in place to hold the sear spring while you check for contact as the hammer releases.

Other possible problems could be insufficient center leaf tension on the disconnector, or a hammer thats out of spec.

The thing of utmost importance is that you have a safe firearm, so take it to a qualified smith if needed.

[tundraotto]

sounds like your trying to become a 1911-smith....nothing wrong with that......get your gun to a smith. (He doesnt care what parts you put in there).

[walmart_ar15]

Hard to diagnose without examining everything. I'd suggest adjusting your over-travel screw to 1/2 to 1 turn out from where the sear clears the half-cock notch; you can drop the main spring housing, remove the hammer strut from it for easier checking, then slide the msh back in place to hold the sear spring while you check for contact as the hammer releases.

Other possible problems could be insufficient center leaf tension on the disconnector, or a hammer thats out of spec.

The thing of utmost importance is that you have a safe firearm, so take it to a qualified smith if needed.

+1 I would also remove the grip safety so u can see inside.

[modls7]

Also check to ensure you have enough pretravel. The trigger won't reset properly if this is too low, it sounds like you have not checked this.

[markw]

Try backing out your overtravel screw. The sear isn't moving far enough out of the way of the hammer. You said it was a used hammer, does it do this with the original hammer? Did you put the hammers side by side and compare?

[littlejake]

How old is this 1911. The production process for US military 1911's required essentially every part to be hand fit. Parts were not drop in. There are specs as noted in Kunhansen Shop Manual for US Military 1911 Pistols. Even if you have new parts that are right on spec, dropping them into an old US GI frame will not work -- unless one is extremely lucky.

It's pretty obvious the sear-hammer geometry is wrong. The sear was tripped from full cock but caught the notch at half-cock -- right on the tip not fully in the notch -- and that broke the sear.

You need an experienced 1911 pistol smith to fit new parts. They are a dying breed -- but there are still some folks out there who have the skills and are passing on their knowledge so it's not lost forever.

[Kruzr]

I agree with markw, back out the overtravel screw 1/2 turn and see what happens.

[wash]

The overtravel screw is backed way out, I'm sure that is not the problem.

I will buy some pins gauges to do the hammer and sear off the side of the frame trick.

I'm starting to think that my hammer hooks are way off but I haven't bothered measuring them.

The 1911 in question is a Charles Daly (Filipino) that is about 8-9 years old and might have 300 rounds through it.

I haven't compared the hammer to the old pieces yet, mostly because the old stuff looks like it might have come out of a crackerjack box, lots of parting lines and rough surfaces.

I'm just trying to get it good enough to do dedicated .22 duty with the Kimber kit I bought a while back.

I'm still surprised that the Kunhansen manuals don't list my symptom in the troubleshooting guide. I can't be the first person to see this issue.

[modls7]

Did you check the pretravel? Also, how heavy is the trigger pull? This is not an uncommon issue.

[Kruzr]

The overtravel screw is backed way out, I'm sure that is not the problem.

So this isn't the case then:

I do have a trigger with an overtravel screw but it is adjusted to allow at least 0.050" of travel after the trigger breaks.

You need the allowance on overtravel after the sear is fully tripped not after the trigger breaks.

[wash]

No, 0.050" is a lot of trigger travel.

At this point I'm not sure if it's bottoming on the overtravel screw or the actual trigger shoe.

When I shoot I'm certainly not going to pull the trigger 0.050" further back after it breaks. What I have been doing is pulling the trigger until it breaks and then letting the hammer go forward while the trigger is in that position. When I do that the sear catches the half cock notch.

I'm pretty sure if I pull the trigger back as far as it will go the same thing will happen.

I'm not sure about pre-travel, it obviously goes forward enough to engage the sear on the hammer hooks and there is a little play before I can feel sear spring pressure.

Before the EGW sear broke the trigger felt real nice, light pull, not gritty and a clean break. It seems a little heavier with the STI sear but still nice.

I was intending to adjust the overtravel after establishing proper function, then fooling with the pre-travel tab on the trigger bow after the overtravel was adjusted and working good.

I didn't get that far.

[modls7]

No, 0.050" is a lot of trigger travel.

I'm not sure about pre-travel, it obviously goes forward enough to engage the sear on the hammer hooks and there is a little play before I can feel sear spring pressure.

If you don't understand how pretravel works in a 1911, you might want to quit before you break more quality parts and especially to prevent making an unsafe handgun that you "think" works. Send it off to a gunsmith, have him explain what is going on.

I'm all for tinkering, but typically you want to have all of your ducks in a row before for messing with safety critical parts. That means fully understanding the working relationship of all the components and their adjustments, not leaving one or two out. You also need all of the facilities needed to ensure proper working relations, and it seems you are ill-equipped.

[Kruzr]

No, 0.050" is a lot of trigger travel.

Really? Your half cock notch is 0.100 - 0.110 in height. Total mimimum trigger travel for a 1911 is in the range of 0.125 - 0.140.

If it were insufficient pretravel, the trigger won't reset.