Commander locking open before empty


September 18, 2004, 09:32 PM
I was shooting my Colt commander series 80 today. At one point, the slide locked open after the first round. Thinking I might have hit the lever, I paid attention to how I was holding it. It locked open again after the 3rd round. The remaining dozen or so rounds were OK.

I was not able to move a round in the magazine forward or left far enough to hit slide lock. So I don't think that was the problem.

Gun is almost new, maybe 300 rounds through it. Winchester 230 gr ball. Magazine was a Mec-Gar.

Anything I can check for?

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September 18, 2004, 10:16 PM
1911 Tuner is the guy you want to ask, but where'd the clip come from? It's not OEM and I think I'd experiment with different ones.

September 18, 2004, 10:16 PM
Check the slide stop and see if the bullets in the mag are hitting it and nudging it up.

I ran into this problem in my Commander. I took the slide stop and carefully stoned down the area where the bullets were rubbing.

With the pistol disassembled, if you put a magazine with a couple rounds loaded (be very careful! only in a disassembled pistol!) and insert it in the mag well, you can see if they are hitting the slide stop. Slide the top round forward a bit as well, as that can happen when firing.

It took a few times for me to get it to the right amount of stoning to stop the problem. Be careful not to take off too much metal, or your slide won't lock back when the mag is empty.

September 19, 2004, 12:21 AM
PinnedAndRecessed -
It's an almost new Mec-Gar magazine.

I tried checking for bullets or cases hitting the slide stop and I couldn't get one to move close enough to hit it.

September 19, 2004, 06:38 AM
Hmm my next guess would be to check if the plunger tube spring is too soft (not putting enough tension on the slide release lever so it's "bouncing" up under recoil) - but I'm now gonna punt and say, "See what 1911Tuner has to say."


September 19, 2004, 07:51 AM
Howdy Ruger,

FJC and P&R pretty well nailed it. There's maybe one other reason, but it usually doesn't show unless the slidestop is an extended type or the area where the plunger pin makes contact is wrong.

Inertial mass...heavy stop...will sometimes cause one to bounce upward
enough to engage the slide and stop it. When it happens, it's usually just
barely catching on the corner. If the stop is standard, it can happen if there's not sufficient clearance bwtween the stop and the slide.

Magazine out, pull the stop down as far as it will go and hold it. Use a feeler gauge to chack the gap betwen the top of the stop and the slide.
I like to see .012-.015 inch...but .010 will usually do unless the plunger spring is seriously tired. Check the pin may be worn flat on the end,
which changes things and reduces engagement tension a little.

Be aware that even though you can't see the side of the bullet making contact with the lug by manipulating it manually, doesn'yt necessarily mean that it's not happening. The dynamics of live firing is a little different, and
things could be flexing just enough to let it happen. Not likely...but still a possibility. I'd say that if there's as much as .015 inch clearance, it's probably not contacting, and something else is in the works.



September 19, 2004, 08:16 PM
1911Tuner -

I'll check the clearances and report back here if they're too close. I can try a different magazine too.

Thanks all

September 21, 2004, 12:32 AM
Did you try any mags other than the Mec-Gar's? I bought 2 Mec-Gar mags to use in my Charles Daly 1911 and my RIA Commander. Neither one worked in the CD (slide locked back every 2 or 3 shots). Both worked in my RIA. Both worked in my buddy's RIA Commander. Only one worked in his Springfield.

The gun store owner said that was a common problem with Mec-Gar mags in 1911's. He replaced them both. Both worked in all of the above guns.

September 21, 2004, 08:22 AM
Tuner is on the money.

My saga; My Kimber Ultra slide would lock open prematurely (only once or twice every 50 rounds, but that was unacceptable to me; this is my serious biz sidearm!).

OK, slide stops aren't too expensive; I bought one & set the original aside. Did some cutting & polishing at the "contact" point. Result? Occasional premature slide lock continued; now coupled with occasional failure to lock on an empty mag! This enlightened me to the fact that the premature slide lock was definitely inertial, not tolerances. Lightweight pistol + .45 ACP recoil impulse = slide bouncing upward during recoil.

Back to the drawing board.

Second slide stop purchased. This time, I followed a clue I read in a gunsmithing manual. I CAREFULLY dremeled a SLIGHT indentation at the rear of the slide lock, where the plunger engages. PRESTO! Flawless functioning over the past several hundred rounds. Locks when it should, doesn't lock prematurely.

Just what worked for me. . .

September 21, 2004, 09:13 AM
That will work...but ya gotta be careful or you can ruin the stop...and it's back to the drawin' board. The Wilson Bulletproof stop is machined steel,
and has a step milled into it for just that purpose. Some of'em require a little tweakin' so that the stop will lock the slide when it's supposed
some pistols. Others will drop right in and go to work. The Wilson stop is pricey. I'd try a new plunger spring...and pins if they;re worn...before spendin' the money. Always try the cheapest route first.



September 27, 2004, 05:42 PM
OK, I checked a few things.Here is what I found:

The clearance between the top of the slide stop and bottom of the slide was between .017" and .020"; the lower value with the slide pressed down to the frame and the higher with the slide pulled upward.

The spring tension on the plunger seemed the same as that on two other almost new guns. One a Springfield new production WWII, and the other a Colt 1991 Govt model.

When I first checked the bullet clearance, I did so with slide off. I moved the magazine down in the frame until the bullet was next to the slide lock. I checked this again, pushing the bullet to the left and it looked like it could hit.However, I thought the rounds might be in different vertical positions in actual operation, so I checked again with the slide on.

The top round sits above the slide lock, so that this one shouldn't be able to hit it. Then I put an empty case on top in the magazine so I could see the round below it. When the top round pops up after the breechface clears the rear of the case, the round below doesn't move up far enough to reach the slide stop. Not even close.

There is no spring tension pushing the slide stop down, just friction from the plunger pressing against it.

Anything I can look for at the next time it occurs?

September 27, 2004, 06:41 PM
Okay...Looks like no bullet contact on the lug.

If there's a shock buffer in the gun, take it out. That'll do it sometimes...
Don't ask me why, 'cause I ain't quite got that one figgered out yet myself...
but sometimes it will, especially in a Commander.

Have you changed anything about the gun? Did you install an 18-pound recoil spring? If you did, get a 32-coil Wolff GM spring and cut it down to 24 coils and check for coil bind. Trim a half-coil at a time until it doesn't bind.

Does it do it with all magazines...or just one or two? Tolerances will sometimes let a magazine shift to the left just a hair, and let the bullet nose bump the lug. If it's just one, chack that magazine by pushing it to the left while you push it into the well to look for contact.

Standin' by...

September 27, 2004, 07:18 PM
Gun wasn't new but was like new in box. I'm pretty sure everything is stock, but I can't be absolutely certain. But I'll try and check.

I will also try a different magazine.

Here's an idea. The second round down can't reach the slide stop. But could the top round be getting hit hard enough by the ejecting case to move down in the magazine and under the slide stop and then up again?

September 27, 2004, 07:40 PM
Ruger asked:

But could the top round be getting hit hard enough by the ejecting case to move down in the magazine and under the slide stop and then up again?

Not likely...but anything's possible.

The round under the one that's on top is the one doin' the bump if that's what's raising the slidestop. It does it as the slide gets off of it in recoil, and the round nudges the lug as it rises into feeding position...Next time it happens, take notice if the stip is fully engaged or if it's just barely catching on the corner. Full engagement suggests bullet contact...partial engagement usually means inertial bounce. Lightly beveling the back corner cures it once in a blue moon...but it usually requires more. I'd try a
new plunger spring first..and push the mag in until the bullet ogive is aligned with the lug. Stone the backside of the lug a little on the same angle as the ogive and see if it gets any better. If it does...even a're on the right track. The nudge engagement is more likely to happen with factory hardball...strangely enough. A handloaded ball round with a .010 or .015 inch deeper seat on the bullet may cure it completely.
Factory ball OAL runs from 1.255 to 1.270 inch...with 1.260 about average.
Try 1.250 inch OAL and see what happens...or try a cartridge with a truncated cone bullet ogive. Anything to eliminate the obvious. If none of that helps, you've got something else workin'. It's usually somethin' simple, though...Weak plunger spring/worn plunger...Inertia...Bullet contact.
That's about covered everything unless the angle at the back of the stop has been altered.

Dave Sample
September 27, 2004, 07:42 PM
I like Tuner's new red neck pistolwrench john travis stuff. I may change mine to "I make 'em SING and BLING!" It is a slide stop problem. One thing that has not been considered is the back angle of the slide stop and how it's polished back there. There are two angles here and either one could have an effect on this malfunction. Does this 1911 do the thing with semi-wadcutters otr other bullet shapes? Commanders should not have shok-buffs ot guide rods in them in my opinion. The slide stop could be catching the follower but I rather doubt that. The back of the slide stop can be changed to to make it come up harder or softer. I don't care for dimples, either.

September 27, 2004, 07:45 PM
Dave said:

I like Tuner's new red neck pistolwrench john travis stuff.


Dave Sample
September 27, 2004, 08:48 PM
I meant to say "I LOVE IT" !

September 28, 2004, 11:03 PM
The round under the one that's on top is the one doin' the bump if that's what's raising the slidestop. It does it as the slide gets off of it in recoil, and the round nudges the lug as it rises into feeding position... That part confuses me. What it looked like, the second round in the magazine could not rise enough to hit the slide stop when the slide moved back and the top round rose to the top of the magaine.
Then, when the slide moved forward and pushed the top round out of the magazine, the next round could rise enough to hit.
However, the slide is too far forward at that point. The slide notch is forward of the stop.

George Hill
September 29, 2004, 02:12 AM
How can the follower be causing the problem hitting the stop when:
A. This happens as early as the 3rd round in the mag.
B. That's what a follower is supposed to do when the gun is working right anyway.

The bullet shape question is valid, and so is the spring tension...
However if it's already addressed that bullets are not touching it, then it's gotta be that the lever is bouncing. This might not be from the spring - but from a worn or impropperly made lever.

Have you tried a replacement lever from another gun?

September 29, 2004, 06:01 AM
Okay...I re-read my post and can see how you got confused.
Lemme try to do it mo' betta this time...

It's probably either the bump or the bounce...That's what does it 90% of the time. If it's the Bump, here's how it happens.

The pistol fires, and the slide starts back, The next round to be fed isn't
quite in feeding position, but as it moved upward in the magazine to the
pre-feed position, it touched the lug as it moved up, and is probably lightly touching it as it waits to move into full position. When the slide moves bazck far enough to get off the round and let it move into feeding position,
it pushes the stop a little more, and it engages the slide.

To see if the bullet is making contact, install the slidestop in the frame in its normal position. Remove the mag catch from the gun so you won't have to fiddle with it. Load a round or two into a magazine, and watch the area
with a good flashlight while you slowly move the magazine up and down
to simulate the rounds rising in the mag. There should be no contact
between bullet ogive and slidestop lug. None.

If it's the Bounce...Which is rare with a standard slidestop unless something's wrong with the angle at the back or the plunger pins or can be caused by too little clearance between stop and slide...
or even the recoil spring being too light or too heavy. I've seen the recoil spring have an influence on it occasionally. Not often, though.

I'm with George...Try another stop and see if it goes away.

Missouri Mule
September 29, 2004, 08:47 AM
I am thinking ....a new recoil spring mabe ......a X-tra power Wolff.

Worked for me and my Kimber!

September 29, 2004, 10:59 AM
Missouri Mule said:

I am thinking ....a new recoil spring mabe ......a X-tra power Wolff.

Worked for me and my Kimber

Interesting...I've seen premature lock that was related to recoil spring load
three times...and in all three, it was because the gun was oversprung.
Going to a lighter spring solved the problem.

Was your Kimber a full-sized gun, or a shortened variant? Which spring rating did yours respond to?

Missouri Mule
September 29, 2004, 03:53 PM

The pistol I am referring to is a Kimber SS Compact II.
Ammo is 200 gr+p Gold Dots.

It was experiencing premature slidelock with the (22 lb factory spring, per kimber tech.. I installed a 24 lb wolff and the problem went away.

I don't have the answer..I am not a pro.

What I do know is it helped my pistols failure.

I typically shoot standard loads for pleasure and defense / CCW.

I was given a few boxes of the +P Gold Dots to try. I'm not wild about them so I don't carry them.

I was merely offering feedback.... sorry.

September 29, 2004, 05:13 PM
Missouri Mule...NO NO! I wasn't raggin' on ya. I appreciate your input. I was just curious to know the details. I'm still studying the different effects that playing with the recoil spring has...Seems like I hear of something different every time I turn around, and I'm still trying to determine exactly why one change takes it one direction, and the same one in another gun will go exactly opposite to what usually happens. It's almost like practicing medicine...About the time ya thing you've got a specific question nailed, it'll throw a curve, and it's back to the drawin' board.

Sorry if I sounded like I was takin' it wrong. Didn't mean it that way.

September 29, 2004, 09:57 PM
I've a theory that the new PTFE "super" lubes might have something to do with it. I had this happen with my four most recent 1911 guns (Charles Daly EMS, Kimber BP Pro, Kimber BP Ten II, & Springfield Micro Compact). None did it first time out, but started after the initial cleaning and my use of Dupont Perfomance "dry lube".

Seemed random in terms of rounds fired from the mag at the time. And since it sometimes happened with my 200gr lead SWC reloads I figured it couldn't be the "bump" cause the nose is too narrow to ever touch the lug.

I've put little dimples in the slide stop with a small drill bit to give the plunger a litte more to work with. Seems to have solved the problem in all three guns.

OTOH, could be a rash of weak plunger springs going around :)

The slide stop in my Colt GM series 80 had the "bump" but the problem was the "notch" the slide rides in was too wide letting the lug move too far inward. Swaped slide stops with it and my Norinco and problem switched guns. Grinding the lug enough so it couldn't make contact with a 230gr RN bullet caused it never to lock back so I picked up a replacement slide stop at a gun show and problem solved.


September 29, 2004, 10:00 PM
Actually the commander is all stock and new. It's the 1991 compact that was used but like new.

Dave Sample -
The angle at the rear of stop seems close to zero; there doesn't seem to be any tendency for it to move down by plunger spring pressure. Seems the same also on my other Colts and a Springfield. Gun is all stock and almost new.

George Hill -
Haven't tried a new lever yet. All my other levers seem identical. But I plan on trying something different in there.

Missouri Mule -
Did you have other reasons for changing the spring besides that one problem? And did the new spring affect anything else?

1911Tuner -
Just moving the magaine up through the well, nothing touches. But I can force the round far enough to the left so the bullet hits. With the slide on, the top round looks to be always above the stop, even while the bottom of the slide is holding it depressed in the pre feed position.

It is sounding like the stop is just bouncing up, especially since there is no actual downward spring force on it.

Here's a theory I have about the recoil springs:
Maybe everything has to be timed just perfectly for the stop to bounce up just as the notch is passing by. Could that any spring change, either stronger or weaker changes the timing of the bounce. In one case it bounces up too soon to catch the notch and in the other case it bounces up too late.

Missouri Mule
September 30, 2004, 12:45 PM
Sir I do apologize...I din't really mean to be defensive. I reckon I may have transferred a little of the BS from some of the other sites I watch.
Again I am sorry!

I really do appreciate this site!

The solution to my pistols premature slide lock was probably luck on my part. It would occur with four different Wilson mags as well as 2 Kimber mags and 4 different Colt mags.

As stated I am not a professional in any regard to guns.
I have however owned and used various 1911s for more than 20 years.
I am also a tinkerer. I like to solve my own issues. I have also learned that no two 1911 are the same. Like any other mechanical device it will have it's own characteristics and preferences.

So far this is the only 1911 that I've owned which I haven't been able to resolve it's issues by tinkering with it.

That one issue is the occassional FTE after it starts getting dirty or fouled.
I have tried various oils on the rails I have also tried a number of different greases. I have varied recoil spring weights, different loadings etc, etc.

I have learned that with this pistol the factory set up is the most reliable.

I have lighty lapped the frame / slide rails and lightly polished the chamber.
I have also replaced the extractor with Kimbers " dimpleless" version.

Those things seem to have help since it now runs a little longer before failing. Another thing I have noticed is the pistol seems to be a little hard on recoil springs. I also experienced that with a Officer's model I used to own. In that case if I changed springs every 500 rounds it ran nearly flawlessly.

This little Kimber mostly "seems" to just be sensitive to dirt / fouling.

September 30, 2004, 01:10 PM
Missouri Mule said:

This little Kimber mostly "seems" to just be sensitive to dirt / fouling

If your occasional FTF when dirty is a failure to return to full batttery,
it's very possible that the chamber is a little tight...likely right on the low end of tolerance. That seems to be a trend lately, and whenever I drop a finishing reamer in a chamber, I get chips 9 times outta 10.

One thing to check is to see if the barrel rides the link as the slidestop pin
rounds the front radius of the lower lug. If it does, that can cause a light 3-point-jam...aka stem bind. It may not be quite enough to cause a problem until the gun gets dirty.

Kimber's "dimpleless extractor"...:confused: Is it an internal extractor or external? I don't have occasion to run into many Series 2 Kimbers...if that's what yours is...but if yours has the traditional internal extractor,
it may be that it's a little too rigid to provide the springiness that it needs
when the tension is right. There's a simple cure for that...If this applies,
Let me know and we'll see if we can nail your bug. I've been known to
step outside of the traditional lines at times to get one to run.

Oh yeah! No foul, no harm...and I understand completely about some of the other forums.:cool:

Missouri Mule
September 30, 2004, 01:42 PM
My occassional, when dirty failure, is actually a fail to extract. The empty remains in the chamber while a fresh round noses up behind it.

I will try to determine if it is the stem bind failure you described. Thanks!

This pistol is a Series II with the external "Tactical Extractor".

The original factory extractor is actually dimpled, center punched? I assume that is for id purposes ??? Anyway, this one has no dimple. The Kimber rep I spoke with stated, these extractors have been through several revisions.
She called the one she sent me "Dimpleless" and the latest version at the time.
The newer extractor appears to have a slightly longer and wider claw.
Other than that I don't see any real difference.


October 1, 2004, 06:33 AM
Howdy Missouri Mule. Sorry I've been away from this one for a while.

Okay...Sorry I've been off this one for this long.

I've re-thought the question...again...and come up with an alternate theory on the mechanics of the event. See if it makes sense.

Both are due to the stop jumping into engagement under recoil, but two different forces are at work. In my case...recoil spring being too heavy...
inertial response is the bug. I've noticed that the heavier the spring, the more the gun fights my grip, and my had tires faster than with a lighter spring.

In your case...the stop pops up into engagement due to higher impact
energy between slide and frame...and the heavier spring softened that impact enough to either reduce/eliminate that rebound effect...or it occured at a different time. By the time the stop bounced, the window of opportunity...the stop notch...had come and gone. What your spring change did was to alter the timing of the bounce just enough to prevent

My spring change also altered the timing and eliminated the window of opportunity...but in a different way. I may have been able to accomplish the same thing by going even higher on the recoil spring change...but
I tend to think in terms of lower spring rates to keep other timing issues at bay.

Both reasons for the premature lock are related to timing...Both are
cured by altering the timing of the slide, but for different reasons. My guess is that inertia or impact-induced premature slidelock has such a narrow window of opportunity, that the conditions must be just so in order for it to occur...assuming that the slide stop isn't overly heavy, and the angle at the rear isn't out-of-spec....and that if we can change the slide's position just one-tenth of an inch when the bounce occurs, we can eliminate it. A good plunger spring would also work to keep the stop where it belongs, but that's not the whole issue. It's part of the picture, but only one part.

This matter of timing apparently goes deeper than we suspect.

Oh yeah...Don't sell yourself short because you're "Just a Tinkerer". When we get a real problem child that won't respond to conventional adjustments or cures...which often happens...we all become tinkerers in order to fix the problem. That's what a lot of engineering and design entails. Try something. If it doesn't work, try something else until ya find what does...and then use it often to see if it works consistently enough to mark it down in a log for future reference.

Several years ago, I learned one of the most basic lessons of troubleshooting from a guy who used to come hang around and watch me tinker with pistols. he had been brain-damaged due to a bicycle accident when the was about 7 or 8, and his mental state had frozen at about that level of maturity. I had a pistol that just wouldn't respond. He asked me what was wrong, and I told him that I had done everything that I was supposed to do, and the gun wouldn't work. This man-child shrugged
and said: "Well..Then try something that you're NOT supposed to do."
The logic of a genuis came from a man who couldn't even learn basic multiplication tables...but he had the gift of logic that was uncluttered by



Missouri Mule
October 1, 2004, 08:04 PM
Damn Man!
You put a lot of thought into that explanation. I understand what you are saying. In my situation I fell back on my experiences with a somtimes cranky Colt Officer's model. That dang thing would go though new recoil springs in about 400-500 rounds of hardball. At that point it would start throwing fits until I dropped in a spring.

Eventually I got around to trying some Cor-Bons in it. Those things really pounded that little pistol. It would prematurely lock the slide back sometimes every other round. So I tried a 24lb spring setup. Wah Lah!
That fixed that and I ran that spring trouble free for the next ~1000 rnds +/-.

Chances are in this case I probably just got dumb butt lucky.
I tried the heavier spring just because I was shooting +p's

It is my opinion that the Speer 200gr +p's are too hot for this pistol even
with the x-tra power recoil spring. I don't intend to use them anymore in this Pistol. They work great in my 5" Kimber though.

It makes me feel good though that a man of your experience and a man of my experience ,Ha! Ha!, seem to have come to roughly the same conclusion in similar but separate situations.

I bought a plunger detent spot drill to try if it pops up again.
And, I am sticking with standard HP's for CCW.

Thanks again kind Sir!

October 2, 2004, 11:54 AM
Missouri Mule said:

Damn Man!
You put a lot of thought into that explanation.

Yeah. Makes my head hurt sometimes. It's a helluva lot simpler when the lug gets bumped...:rolleyes: :D

October 3, 2004, 12:41 AM
So my theory was pretty good, huh?Here's a theory I have about the recoil springs:
Maybe everything has to be timed just perfectly for the stop to bounce up just as the notch is passing by. Could that any spring change, either stronger or weaker changes the timing of the bounce. In one case it bounces up too soon to catch the notch and in the other case it bounces up too late.
Anyway, what is the best way to fix it? Do I want to change the angle on the rear of the lever? Or cut a small indent?

Are the Colt parts expected to work by friction pressure alone?

October 3, 2004, 07:48 AM
Friction and spring tension on that plunger pin, RJ...

Yep. Your theory was logical. As to whether yours OR mine are correct is anybody's guess...:p

So...We're back to "Try another stop and see what happens. Put a new plunger spring in it and see what happens. That's the way these things go sometimes, and we're reduced to mere tinkerin' to find the cure...:cool:

Tuner <---Proud to be a Tinkerer

October 3, 2004, 08:18 PM
Tinkerin's good. Something to do when not shootin'.

OK, that should give me some things to try.

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