1911 question (Paging Fang. . . )

[Cyrano 4747]

Quick question for the 1911 gurus in the house (Fang) -

I was out today shooting with my father in law and he brought out his 1911, an old USGI Colt made in 1942.

Anyways, once in a while (I'm gong to guess once every other magazine or so) it would not come back to full-cock after firing. It would shoot normally, then after it cycled it would have one in the chamber and be at half-cock. Thumb back the hammer and it would function just fine.

Since it's an old gun I'm guessing something in there is just worn and needs to be replaced. Any ideas on what that would be? The gun was brought back in the rucksack of my father-in-law's step dad and, as far as he knows, fired maybe a dozen times since the war. It's almost in the white from holster wear, but most of it is in pretty good mechanical shape. So, while it's not shot out or anything, I could also fully believe it still being 100% as it came out of the factory in '42, including the springs.

It shoots BEAUTIFULLY for what it's worth. Fist sized groups at 25 yards, slow fire.

The research I've done so far has people recommending, for guns with the exact same problem, replacing the hammer, mainspring, sear, and/or disconnector, or any combination of those parts. Is there any way to diagnose what the problem part is or could be that doesn't involve me ordering and taking a bag of parts to the range and swapping them until I find a combination that works?

Before someone starts flying the "go to the gunsmith" flag remember that this isn't my gun and the guy who owns it isn't the type to spend money on a gunsmith. If I don't fix this it's probably not going to get fixed until it ends up in my collection as an inheritance, which will hopefully not be for decades. I'm competent to do any minor filing or fitting to get a replacement part in there, but hammer/sear/etc don't seem like the sort of thing that should need a ton of fitting. I"m not looking to create a custom trigger job, just restore it to normal function.

Also, what should the sear/hammer interface on a 1911 look like. Can anyone throw me pictures of a good one and a heavily worn/dangerous one?

Again, when it comes to 1911s I know enough to strip them and put them back together, but as I don't own one or shoot one regularly I know far more about what markings should be on a pistol made in a particular year than I do about how the internal surfaces need to interact and how the geometry needs to go together in order to be safe or what a dangerous wear pattern looks like.

[terraformer]

It sounds like the slide didn't go back far enough to hook up on the catch. The answer may be a good cleaning and decent ammo.

That or the magazine is bad. Did this happen on the same magazine all the times it happened?

[Cyrano 4747]

It sounds like the slide didn't go back far enough to hook up on the catch. The answer may be a good cleaning and decent ammo.

That or the magazine is bad. Did this happen on the same magazine all the times it happened?

Hrm, you know, I hadn't thought the magazine might be the culprit in a hammer problem. I should have tested that when I was out there. The magazines were both 8 round Kimbers. Somewhere between World War II and a few months ago the pair of 7 round USGIs disappeared from the gun and, in preparation for our range trip, he bought the Kimbers. We also had another USGI that I snagged from Miso about a year back (and which I think I might still owe him a couple bucks for. . . ) but it was left in the trunk of the car by accident.

The ammo was Remington UMC. It was the only non-defense ammo that I could find anything like locally to us. I'm more familiar with their "hilariously dirty but not TOO crappy" reputation from 9mm. Are they known to be under-loaded or anything?

The gun was as clean as a whistle when we took it out. Back when I first started dating my wife I cleaned it for him as a favor and took sixty years of filth out of it. It hadn't been shot since then, and when I detail stripped it last night it was still quite clean (minus, of course, the breech face, barrel, etc. from ~150 rounds of firing).

The gun was freshly oiled, and had a little grease in what I believe were the appropriate places - or at least what I read were the appropriate places back when I first cleaned and lubed this gun a year and a half ago. From what I recall from back then, I put a few drops of oil on the rotating parts and a thin film of grease on the frame rails and at the barrel/bushing interface. I don't recall exactly where I found the lubrication diagram I used, but they were pretty emphatic about needing a fine coat of grease on all the sliding parts. I don't THINK I over-greased anything (I used a REALLY thin film) but I'm not going to discount the possibility either.

On a suggestion from another forum I mounted the hammer and seer on the outside of the frame using the mounting pins to hold them in place in order to check the sear engagement. Again, I'm no 1911 expert, but the surfaces don't look worn or in danger of slipping against each other to me. I'll get photos up once I find the cable for my camera.

[Fang]

There could be a number of things causing this. There's the aforementioned short-stroke; the sear spring could be weak, thereby not pushing the sear back into engagement in time; the mainspring could be binding on occasion, creating the short-stroke; the sear could be coming out of engagement, either due to bad geometry on the part of the sear nose or hammer hooks; and the disconnector could be worn down.

And in the ever-lovable fashion of 1911s, it could be some or all of these in conjunction.

The good news is that it's unlikely to be the hammer/sear geometry because when those start to go they tend to do so in a very frequent and consistent manner. You can inspect the engagement visually on the outside of the gun using either specialized fitting pins or the 1911's own hammer and sear pins, but the information this provides may not useful: Sear engagement issues that would occur as infrequently as you're describing would occur at the thousandths of an inch or minutes of angle in parts that already require a magnifying glass to see. Also, sear angles are a dark art where the correct way of doing it is hotly contested and JMB's original intent is unknown and debated.

One test you can do to check the hammer and sear is to take the assembled handgun with the hammer cocked and press on the back of the hammer like you're trying to push it down. Don't jam it under a table and pull up with all your might or anything, but give it a firm and consistent push. If it doesn't push off, geometry is not likely to be a problem.

You could also test to see if the disconnector is a potential problem. Take the slide off and lower the hammer. Holding the trigger back and gripping the gun (so as to disengage the grip safety), cock the hammer all the way back and see if it stays. (It should.)

It's unlikely that underpowered ammo is short-stroking the pistol: If memory serves, the slide coming back far enough to pick up a new round guarantees a cocked hammer. Could be wrong on that one, though.

My guess is a worn sear or recoil spring. If the 1911 hasn't been touched since the 40s and has been used during the war or afterward, these are likely due to be replaced anyway. You'll want a 16-pound recoil spring and either a Colt or Wolff standard sear spring to restore it to factory settings. The mainspring is probably fine, although it couldn't hurt to replace it with a factory 23-pounder while you're at it so that you get a chance to clean out the mainspring housing while you're in there. Remember to replace the firing pin spring if you replace the recoil spring.

If all of the above tests show no problems, then I'd just overhaul the springs for starters. It's probably needed anyway, and even if it doesn't fix things, it will cross out one potential cause.

[Snarlbuckle]

I had a very scary experience the first time I completely disassembled and reassembled my 1911. What I experienced may help you a bit.

During reassembly, I somehow positioned the sear spring incorrectly without noticing. The result was that the sear would not engage like it should have. After a few shots at the range, the hammer was completely decocked. The gun could very well have gone full auto on me, or worse slamfired and gone full auto. Needless to say, I was scared beyond belief. Against my better judgment, I loaded up, griped the gun very tightly, and tested it a few more times. There were no slamfires and no full auto. The problem seemed to happen about once for about every 4 or 5 shots.

I disassembled the weapon again, checking every part touching the hammer and making sure it was all where it should be. It turns out that there wasn't good contact between the sear spring and the sear disconnect. I reassembled it making absolutely sure that the sear spring was where it should be. I noticed at this point that the way the sear spring never really pushes the sear disconnect with any sort of good mechanical leverage. It sort of slides along the slope of the sear disconnect.

Check the contact between your sear spring and everything else. Make sure the surfaces are all clean and smooth. As fang stated earlier, replacing the springs isn't a bad idea.

Also, make sure there's not too much lube in the sear area. I personally give all of my parts a light coat of Eezox and then wipe off any excess. This prevents any gunk from forming while still protecting against rust.

TLDR; Replace your springs, check the surfaces of your sear and sear disconnect, and give it a good cleaning with Eezox. Reassemble and put some good old hardball through it.

[Cyrano 4747]

Bah, it looks like I'm going to have to replace some parts.




One test you can do to check the hammer and sear is to take the assembled handgun with the hammer cocked and press on the back of the hammer like you're trying to push it down. Don't jam it under a table and pull up with all your might or anything, but give it a firm and consistent push. If it doesn't push off, geometry is not likely to be a problem.


Yeah, it failed this test. With this in mind, and looking at some pictures that I snagged on another forum of Kuhnhausen's 1911 shop manuals it APPEARS as if the sear edge could be rounded and worn.



You could also test to see if the disconnector is a potential problem. Take the slide off and lower the hammer. Holding the trigger back and gripping the gun (so as to disengage the grip safety), cock the hammer all the way back and see if it stays. (It should.)



It also fails this test. If the sear is worn would it fail this test as well, or does this indicate that both the sear and disconnector need replacing?

While I'm at it I'm going to order all new springs on the basic principle of "new springs in a gun are almost always a good thing," but which parts in particular do you think I need to get? How much wearing into each other is there with the hammer/sear interface on a 1911?

The owner wants to keep shooting it (although I wish he'd just buy a new handgun and let this one go to a nice, dignified retirement - luckily he doesn't shoot it often, however). As I said before, the finish is quite worn. If at all possible I would like to avoid replacing the hammer - a newly finished hammer with no external wear would just look wrong on this gun. That said, if it needs replacing, it needs replacing.

So, after the springs, what exactly do you think I should be ordering? New sear and new disconnector?

Also, are there any particular companies that you recommend for good, in-spec parts? Cost isn't so much an issue, but this is a USGI pistol through and through so I don't need anything fancy. If I wasn't concerned with buying someone else's worn out parts I'd just get USGI replacements.

[Snarlbuckle]

I'm sure one of your local gunsmiths has a few perfectly good hammers and sear disconnects laying around. If not, I know one who probably does in my area. If you're lucky you might even find an old GI hammer.

[Cyrano 4747]

I'm sure one of your local gunsmiths has a few perfectly good hammers and sear disconnects laying around. If not, I know one who probably does in my area. If you're lucky you might even find an old GI hammer.

All of my local gunsmiths are massive, massive ripoff artists. We're talking $50 fees to throw a headspace guage in a chamber here. If you've got a good line on in-spec quality parts I'd be happy to hear about it, though.

[mbquimby]

All of my local gunsmiths are massive, massive ripoff artists. We're talking $50 fees to throw a headspace guage in a chamber here. If you've got a good line on in-spec quality parts I'd be happy to hear about it, though.

I feel your pain. The most well known shop around my town tried to charge me 50 bucks to take the barrel nut off of my AR when I lost my tool. I laughed at him, bought a new barrel wrench, and never returned.

I hope you get the Colt working. If you're lucky, you'll be able to find the problem and fix it with GI parts.

[Cyrano 4747]

I feel your pain. The most well known shop around my town tried to charge me 50 bucks to take the barrel nut off of my AR when I lost my tool. I laughed at him, bought a new barrel wrench, and never returned.

I hope you get the Colt working. If you're lucky, you'll be able to find the problem and fix it with GI parts.

Well, I'm a bit wary of using GI parts, mostly since I don't want to just buy someone else's worn out problem sear. Honestly I still don't see the problem with the geometry on it, but looking REALLY HARD through a jeweler's loupe and comparing it to some of those pages from the Kuhnhausen book I can kind of see that it is probably worn. That said, I'm equally sure that I could sell it off as a "used, good condition surplus part," especially online and especially to someone like me who doesn't have an eye for spotting those very slight differences.

If it comes down to replacing the hammer I might go the USGI route, but that's mostly because of the fact that about 99% of the hammers I'm seeing out there are just visibly very, very wrong for a USGI gun. Even excluding all the skeletonized this and bobbed that BS a lot of the "USGI" hammers have totally wrong texture patterns or general shapes to the area where your thumb goes when manually cocking it back - usually they're far too squared off, instead of having the proper semi-circular shape to the back.

[bunnielab]

Well, if you want to go the crazy route you could find someone to use a TIG welder to build up the sear and then file it back to spec and then re heat-treat/harden it.

For a non crazy option try giving USFA a call. They make spot on perfect repos of Single Action Armies and while I have no direct knowledge of their line of 1911s, they do claim to be prefect replicals so maybe one of their sears might look right.

[Fang]

Unfortunately, the sear is one part that is not likely to be a drop-in fit. What you could do is just try a sear out of the package and see if it works; if it doesn't, you at least have a spare part. I like Ed Brown sears, but they don't come with the secondary angle cut, and without the secondary angle in there it's not likely to work too well.

I'll continue searching for drop-in sears, but the phrase "drop-in sear" is likely to be an oxymoron.

[Cyrano 4747]

So how much hand fitting are we talking to get a workable sear here?

Does this involve me carefully working the surface of the new sear with a stone in order to get the right engagement, or is this something that pretty much HAS to go to a gunsmith?

Also, I've been reading around on some 1911 forums, and I'm also seeing a bunch of guys saying that when you replace the sear (and possibly hammer) you generally have to replace the thumb safety as well.

What the christ?

Is this true, or are these guys just nuts. This is really quickly turning into gutting out all the interior components just to fix a problem with a single worn surface.

[Fang]

So how much hand fitting are we talking to get a workable sear here?

Does this involve me carefully working the surface of the new sear with a stone in order to get the right engagement, or is this something that pretty much HAS to go to a gunsmith?

Also, I've been reading around on some 1911 forums, and I'm also seeing a bunch of guys saying that when you replace the sear (and possibly hammer) you generally have to replace the thumb safety as well.

What the christ?

Is this true, or are these guys just nuts. This is really quickly turning into gutting out all the interior components just to fix a problem with a single worn surface.

Fitting a sear requires getting the primary angle right, so that it engages positively. A positive sear engagement means that the hammer and sear mating surfaces are arranged so that spring pressure on the sear and hammer makes them naturally fall back into their base positions. A neutral engagement would let you pull on the trigger a bit and let go, leaving the hammer and sear where you'd left them. This is dangerous, but not as dangerous as the third and last kind of engagement, which is negative. Negative engagement means that the sear and hammer naturally tend to slip off each other, which is what you've got now.

So you have to get the primary angle right, and this depends in part on the hammer hooks being at least square to the flat of the hammer, and preferably at a slight angle to capture the sear. This may not be the case with your hammer. Then when the primary angle is set, you have to cut the secondary (aka breakaway) angle.

None of this is especially difficult, but it does require some special tools and you should be prepared to ruin at least one or two sears in the process of getting it right.

Also, what those guys say is correct. Sometimes you need a new thumb safety when the sear is replaced. The thumb safety blocks sear motion, so if your old safety was filed to fit a larger sear than the one you use as a replacement it may stop working or cause the hammer to drop when you take the safety off.

Also, as alluded to above, it might not just be a single worn component causing this behavior. If your hammer hooks are at too great an angle, that could be the culprit, too.