1911A1 Problem, Help Please


July 26, 2008, 09:49 PM
Hi All,

I need some help with a problem that surfaced this past week on my govt surplus 1911A1 Ithaca. Had an accidental discharge while chambering the first round from the magazine. I don't use the slide stop to release the slide I pull back on the slide and release it that way and this time the hammer followed the slide fwd and fired. I unloaded and tried to repeat and initially couldn't. However if I make the grip safety and release the slide with the slide stop lever it happens 100%.

I tested about 100 more times the way I normally chamber a round and it will happen once in a while, I.E.. every 40 tries or so, but 100% of the time if I use the slide stop lever.

Which part/parts should I start with replacing.


If you enjoyed reading about "1911A1 Problem, Help Please" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
The Tourist
July 26, 2008, 10:00 PM
I would change out the firing pin spring.

If it was strong, the forward motion of the slide would not be enough force to let the firing pin fly forward.

As you know, the reason they call if an inertial firing pin is that the overall length of the pin is too short to reach the primer. The force of the hammer drives it forward against the spring, and the spring is strong enough to carry it back.

In your scenario, the pin is reaching the primer.

July 26, 2008, 10:08 PM
Hey there;
You have a bad sear. The disconnect could be bad. But sounds like tha hammer and sear are not talking.

The Tourist
July 26, 2008, 10:12 PM
Yup, sear is the better idea.

July 26, 2008, 10:54 PM
If the hammer is riding the slide into battery stop using the pistol immediately. Sear isn't engaging the hammer hooks, it could simply be the hooks are too worn to hold properly or the sear edge has chipped. Could also be that the sear spring is too light, if I remember correctly it's the far left leaf of the mainspring, either way you now have a full auto pistol. If you have to ask this question, the pistol needs to see a smith, you are about to get into the guts of this 1911. P.S. Ithaca's are for collecting, get a cheapo 1911 to shoot!!

Jim K
July 26, 2008, 11:16 PM
That gun should not fire from firing pin "creep". That only happens (and then rarely if the safety is not engaged or there is no FLGR) if the gun is dropped muzzle first onto hard steel or concrete from six feet or more.

A hammer followdown will not usually fire the gun. Unless the gun has been treated to a "trigger job" by an amateur, either the hammer or sear is in bad shape. What happens is that the full cock engagement is too light, and the half cock notch is not engaging at all. The result is that when the slide slams into battery, it jars the hammer off the full cock notch and it falls all the way, firing the gun.


July 26, 2008, 11:27 PM
What ammo? High primers in reloads might do it. Mind you, Jim has a good point too. An improperly done trigger job can make any pistol unsafe.

July 26, 2008, 11:40 PM
It's not new/used, I've had it for almost 20 years. It just started this. Haven't done anything to it in all these years. It isn't per se a full blodded Ithaca it had some colt parts in it as well. I'm guessing it was like the ones on my ship when I was in the Navy. After firing they all got stripped down and cleaned in a big bucket of parts and then reassembled by the ships armorer piece by piece.

Also since I break it down completely pretty much the same way to clean it I wouldn't really hesitate to attempt replacing the maligned parts, I either manage to fix it my self so that it's safe or I buy another set of parts and have a smith install them for me.

July 26, 2008, 11:58 PM
You could do it, if ya like to tinker, take off the slide and grips, then punch out the mainspring housing pin, the rest of the information is on-line. Take a close look at your hammer, sear and mainspring. If the trigger was light to begin with it could just be the mainspring is getting old. My bet is the hammer hooks are worn or the sear edge has chipped. Look closely to examine the pins that hold these parts for excessive wear. Replace if necessary, the pin holes should be perfectly round, make sure they aren't wallowed into ovals. Hold your hammer and sear together to make sure they mate together well, sear should engage both hooks, not just one side. You should have found your problem by now, good luck! P.S. the hammer strut pin is small and has a tendancy to get lost as it falls out easily, watch for it. The pin that is holding tension on your thumb safety is also spring loaded and can fly three to four feet, so when your wiggling that thumb safety loose watch for it to come out. Get proper fitting punches as well, we don't want to gouge the frame. You get done with this job and you will have an intimacy and confidence with 1911's that only comes from experience.

July 27, 2008, 12:07 AM
Hey there;
My books don't show this gun. How old is it. Maybe you should get it repaired and put it away.

July 27, 2008, 12:14 AM
He has an Ithaca, WW2 sidearm, and rare as heck.

July 27, 2008, 12:17 AM
It's a WWII shooter-grade....it needs to be fixed, then shot....nice gun, enjoy the tinkering, and keep the parts replaced, especially if the hammer is bad....try www.amhurst (or amherst)depot.com for a spare hammer if needed....they also have/had other GI small parts.

July 27, 2008, 12:23 AM
He has an Ithaca, WW2 sidearm, and rare as heck.

They made over 335,000 guns...

July 27, 2008, 12:45 AM
{It's a WWII shooter-grade} So you have seen this pistol? 335,000 is a drop in the bucket compared to the number of RR's, not quite as rare as Union S&S, but still costly to replace.

July 27, 2008, 01:19 AM
hammer and sear, also the sear spring.

if i took it down far enough to do that i would also go ahead and replace the main spring too.

if i did all that i would just finish the tune up with recoil and firing pin springs.

July 27, 2008, 01:29 AM
Guy's it's a shooter. I carry it while hunting small game, and mild range practice. It is old, s/n# on the frame is 393XXX and a NM Barrel s/n# 145XXX.
My CCW piece is my H&K P2000 in .40 S&W. I just want to fix it so that it's safe to shoot again. I'll bet I only shoot 300 rounds a year thru it, just enough to stay proficient so I don't waste ammo when I shoot at a bunny/squirrel. Did get a turkey with it once though.

Someone asked earlier about the ammo, It was Factory Remington 185 JHP. I normally shoot my reloads, 200 gr. SWC @ 900 fps., really accurate and never a fail to fire or feed in 20 years.

I'll take it apart again tomorrow and check the sear/hammer notches, replacing the springs was something I was already considering, I've never replaced them to date, but it was shooting so well I didn't want to mess with anything yet. Maybe I'll order a whole spring kit to make sure I get everything.

Thanks for the suggestions so far.

July 27, 2008, 04:41 AM
It is not about ammo, or firing pin springs.

As several here have mentioned, you have a sear and/or hammer problem.

One thing you can check before you replace either the sear and or the hammer is the sear spring.

I have seen some 1911's reassembled improperly and the sear spring is impinged in some way an not working properly. Or the sear spring has lost much or all of it's tension and is not keeping the sear under pressure.

If you replace either the sear and/or the hammer, I would replace the sear spring too, if you haven't done it recently.

The other folks here have described the sear/hammer situation well enough. Just don't forget the sear spring too.

And, forget what anyone tells you. It is your weapon, sounds like you are using it as it was intended to be used.

Good luck


July 27, 2008, 07:19 AM
However if I make the grip safety and release the slide with the slide stop lever it happens 100%.

There's the clue.

As Mr. Keenan noted...a simple followdown won't fire the gun, even if the firing pin spring is weak. The hammer is being tripped...jarring off the sear when the slide slams into battery.

When you "make" the grip safety, the trigger can reach the disconnect, which in turn presses on the sear. So, Problem One is caused by inertial trigger bounce nudging the disconnect.

Problem Two is that...when the above occurs, the sear usually moves just enough to let go of the hammer hooks...resets quickly...and grabs the half-cock notch, stopping the hammer. That obviously isn't happening.

That means that either the sear spring isn't applying enough tension on the sear to reset it in time to make the half-cock...or something is interfering with it so that it can't reset. It may be badly gunked up, or it may be the fault of the sear spring.

Because the trigger is nudging the disconnect under inertia...it suggests that the sear spring is either badly worn/weak...or that somebody has "tuned" it for a lighter trigger action. I suspect this one, since that entails bending both the sear and trigger/disconnect legs of the spring...and you have both issues in play.

Replacing the sear spring with an OEM Colt spring...available from Brownells, listed in the Colt factory parts section of the catalog...will likely solve the problem.

Of course, this doesn't mean that you don't also have bad hammer/sear engagement. If the problem occurs after a thorough cleaning and replacing the sear spring...it's time to have a look at the hammer, sear, and disconnect...as in replacing the parts.

Replace the mainspring while you're at it. Wolff. 23#...and clean the mainspring's channel in the housing.

July 27, 2008, 07:46 AM

As usual you know the whys and wherefores, and of course you say it real pretty too.



July 27, 2008, 07:57 AM
Thankee, chief.

awizard...if you don't know the detail strip procedure...sing out. It's pretty easy on a stock GI pistol.

July 27, 2008, 08:03 AM
Thanks Tuner, Been waiting all night for you to show up on this.. Yea, I detail strip every time I clean it. I'll pick up a new sear and recoil spring Monday. P.S. the gun had already had a trigger job before I bought it, part of the selling point all those years ago it's about 3 lbs...

July 27, 2008, 09:21 AM
P.S. the gun had already had a trigger job before I bought it, part of the selling point all those years ago it's about 3 lbs...

Oh, Lord...

The issue may be with the hammer hooks, too...and probably more of the bug resides there than with the sear.

Has the half-cock been altered?

July 27, 2008, 05:17 PM
Tuner, I didn't do the trigger job, I believe a smith did it but I couldn't tell you for sure. Seems like the guy told me he'd paid $80.00 for the trigger job. And there's no telling how long before I bought it that he'd had it done.

Anyway Half cock is still there and functions correctly, as does the thumb safety. I'll bow to your expertise but wouldn't you think after 20 years and 8-10k rounds that I've shot, it could just be the sear spring as you suspected?

I'll check out the Sear and Hammer hooks as soon as I can, I work Nights 6pm-6:30 am and today I have to take my wife to work as the youngest has her truck, hence I'm up early today. But while I'm out I'll swing by my local shop and see if they have a sear/recoil spring or if I have to wait to get them tomorrow.

Thanks again.

July 27, 2008, 05:45 PM
wouldn't you think after 20 years and 8-10k rounds that I've shot, it could just be the sear spring as you suspected?

Possible...especially seein' as how it started suddenly. Also possible that the hammer hooks have worn.

Original spec hooks were long by "trigger job" standards...and undersquare...providing a captive engagement with the sear. Hammers that have been prepped for trigger jobs such as the one that your pistol has are cut square and shortened, providing a neutral engagement.

As they wear, they become oversquare, and the engagement becomes negative.

With a positive/captive engagement...pulling the trigger causes the hammer to move backward...overcocking it a few thousandths.

With oversquare/negative engagement...the hammer will move forward a few thousandths as the trigger is pulled. This is a dangerous condition as the force of the mainspring works to squirt the sear away from the hammer and out of contact with the hooks.

You can see which yours has by mounting the gun in a vise and using a dial indicator on the hammer to see which way it moves when you pull the trigger slowly.

July 29, 2008, 03:10 AM
Ok, Update... Thanks for all the suggestions and here's what I've done.

I striped it down and inspected the sear/disconnect and hammer hooks under my lighted magnifying glass and all looked good as I compared it too some of the visualization drawings on the Brownells web site. I replaced the recoil and firing pin spring with the Wolff set @ 18.5 lbs (all they had in stock) and replaced the Sear/Main spring with the Clark Custom 4 leaf spring. Those new springs sure looked and felt better.

So far that seems to have fixed the problem, the hammer isn't following the slide down at all but I haven't shot it yet. I should shoot it about Thursday and I'll probably go a head and put 150 rounds thru it before I call it good.

Tuner, That also raised the trigger pull to 4 lbs 3 oz..... Still fine as far as I'm concerned. :D

Hopefully nothing comes back.:)

July 29, 2008, 06:09 AM
Tuner, That also raised the trigger pull to 4 lbs 3 oz

MUCH better!

August 5, 2008, 05:03 AM
Ok, Shot last weekend and put 250 rounds of every different bullet configuration I could get my hands on and only loaded 2 rounds per mag for the first 100 shots or so and never had the problem resurface. :D My pistol even seems to shoot a little softer now with the new springs in place. Thanks to all who helped out and especially to tuner for the specific details of the the sear hammer interaction and related functions.

August 5, 2008, 08:28 AM
Yup. It's usually somethin' simple...

If you enjoyed reading about "1911A1 Problem, Help Please" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!