1911 slide not locking back after last round.

[riverdog]

Colt NRM 1991A1: What are the possible culprits that could stop a slide from locking back? I thought I had resolved the issue when I switched to the Wilson Bulletproof slidestop, but while shooting today it failed to lock back with three different mags. I was shooting seven different WC 47D magazines and it failed on three of them. On the third failure I stopped shooting that pistol and went back to my LBC TRS, which ran perfectly with all seven Wilson mags even though it's still too tight

So what is the most likely issue? The slide stop installed is a new WC BP which I feel good about. I may try a different Colt slidestop, but I really don't think the slidestop is the issue. It did the same thing with the original Colt factory slidestop so I'm looking for other issues.

How about the plunger? Could that stop the slidestop from moving up? What about the plunger would cause this effect.

I noticed some copper on the slidestop where it protrudes into the magazine. Is it protruding too far? Is that even an issue? I have a nice set of files if that's the case, but I would think that copper would tend to push it up early rather than not let it move, particularly after the last round is gone. TIA

 

[Jim K]

Copper on the slide stop would indicate it is coming in contact with the bullets in the magazine, which could give the opposite result, that is, the slide stop would be activated when the magazine is not empty.

It is easy to see what is happening. Just remove the slide, insert an empty magazine, and look down into the magazine well. You should be able to see the magazine follower activate the slide stop. If all looks well, and the slide stop is activated, you might want to check your loads and the recoil spring. If you have light loads and/or a stiff spring, it is quite possible that the slide is coming back far enough to feed a round, but not far enough for the slide stop to catch.

It is possible that the plunger could be a factor, but it seems unlikely, at least on a Colt.

Jim

 

[Baron Holbach4]

Riverdog, the same failure to lock back on the last round occurred
using my Kimber Stainless Target II .38 super. When I switched
to Winchester White Box .38 super ammo, the problem was resolved.

 

[riverdog]

Simple enough to check, I'll take some 230 Fiocchi ball and 230 gr JHP's next time out. They're a little hotter than standard PMC 230 ball. I'm using an 18.5# Wolff recoil spring.

 

[Stinkyshoe]

I sounds to me like a mag problem. But I really don't know anything.

 

[BigG]

Recoil spring on a standard 5" .45 is 16 pounds. Also, since you changed so many things you were apparently not satisfied with the status quo. Why?

 

[riverdog]

It had the same problem with a 16# spring so this problem dates from before the recoil spring was changed. I use Wolff 18.5# springs on all my fullsize 1911's and this is the only one with a problem . I could go back to a 16# spring, but I seriously doubt that will fix it. My other Colts, my Wilson CQB and my LBC TRS all use 18.5# springs and the same WC 47D mags. Only this one Colt has a problem.

 

[Walt Sherrill]

Compare the slide stops, too, while you're at it.

Since you're using the same ammo, same mags and same weight springs, the the combination isn't a problem in other guns, the slide stop may be the only real difference.

 

[BEARMAN]

You said you use a 18.5 spring on all your full size .45's Is this a Commander? And if so, they use a shorter spring. On another approach to the problem is the angle of the slide stop notch in the slide peened and the edge not sharp enough to catch , this happened on one of my .45's after many years and rounds. Also sometimes a " shock buff " that it is too thick will cause this problem. GOOD LUCK ON YOUR SEARCH FOR A SOLUTION.

 

[riverdog]

Walt: I'll use the Colt slidestop from another 1991A1 that runs fine and compare perfomance with the Wilson SS. If it works fine, I'll order up another Colt slide stop.

BEARMAN: It's a 1991A1, full size. I'll check the slide, but it has less than a thousand rounds through it so unless it was defective at the factory, it should be fine.

Range day, thanks for all the input.

 

[Cactus]

If you have this problem with all magazines and every slide stop, maybe your magazine release does not hold the mags high enough to activate the slide lock.

 

[riverdog]

Back from the range.

The Colt slidestop -- just like the original factory slidestop -- locked the slide back early leaving the last round loose, not chambered and not in the magazine, but rather on the magazine. So to review, occasionally the Wilson slidestop won't lock back and occasionally the Colt slidestop locks early. Not every time, but the malfunctions are consistent. To me this says it's something else.

 

[Owen]

uhh, I have this problem sometimes....

Are the stocks on this gun different than on the other guns?

Make sure your thumb isn't riding the slide stop or anything like that.

(I know it sounds dumb, but check it out)

owen

 

[Walt Sherrill]

There aren't many things left to check...

I had a similar problem with a CZ, and found that it was mag springs -- but that was a problem that repeated itself in every gun, not just one of them.

(If the springs are weak, they seem to let the rounds move around a bit, and the top round might nudge the slide stop on the way up. Might. This is all conjecture on my part. In my case, replacing the springs solved the problem. I have no idea that your problem is related.)

Bent or slightly misshapen followers can cause all sorts of strange problems in a 1911, too.

 

[1911Tuner]

Slidestop Woes

Been watchin' this one for a few days.

Riverdog said:

The Colt slidestop -- just like the original factory slidestop -- locked the slide back early leaving the last round loose, not chambered and not in the magazine, but rather on the magazine. So to review, occasionally the Wilson slidestop won't lock back and occasionally the Colt slidestop locks early.
----------------------------------------
The loose round on top is due to the round getting loose from the magazine under inertia during the slide's recoil cycle. The last round rides forward and escapes just as the slide smacks the impact surface in the frame/guide rod head. (Actually, the pistol moves rearward and the round stands still.) With the last round out of the magazine, the follower lifts the slidestop and engages the notch in the slide as it heads toward battery, and leaves the last round laying loose on top of the magazine. Sometimes, the last round will be ejected out of the port just as the slide hits the frame. In the case of an extremely weak magazine spring, the NEXT to last round gets launched, and the gun feeds the last round. Weird things happen when the magazine isn't right.

The causes are:

Weak magazine spring, and/or improper follower design. The little dimple
on the follower is there for a reason, and that reason is to keep the last
round under control. Remove it, and you can have problems, whether you remove it with a file or the design omits it. A good, strong spring will help
some, but probably won't eliminate the problem entirely.

The Wilson Bulletproof slidestop's shelf is designed to prevent premature
slidelock, and it does a pretty good job, even when the lug makes contact with the bulletnose of a rising round. The other cause of this malady is
inertial bounce of the stop into engagement. The problem is that it sometimes does too good a job of it, and prevents the stop from moving
up far enough to engage the notch at all...or at best, only partially engaging it.

My suggestion is to order some Wolff 11-pound mag springs and use them in a 7-round Colt or Metalform magazine with a dimpled, flat follower, and the Colt slidestop. You can use the Wilson stop if you work the shelf a little
so that it will allow easy engagement, but still not allow "bounce". The
trick is to figure out whether it's inertia or contact with a bullet nose. If the Colt stop is bouncing, replace the plunger spring and detent pins with good parts, and your problem will likely disappear.

Don't start grinding on the Wilson's shelf, but rather reshape it and polish
it in the area below the indent to let it ride over the detent pin easier. Go
slow and recheck by pushing the stop into engagement slowly by hand to
"feel" when it gets smoother, and test with an empty magazine to see if
it fully engages in the slide's notch.

I've also occasionally known a too light or too heavy recoil spring cause
a failure to let the slide lock, but it's pretty rare if everything else is good.

Most function issues with the 1911 are simple, and they're usually related to the magazine or the extractor. I can't remember how many 1911s that I've "fixed" by simply handing the owner a good magazine, and telling him to go try again. Sold a lotta magazines that way, too. There's also the matter of improper design and materials on these items...but that's fuel for a whole 'nother thread.

Luck to ya!

Tuner

 

[riverdog]

Tuner,
Your explanation of how a round gets loose on top of the mag makes sense. Maybe I'm in denial with these being relatively low round count Wilson magazines, maybe Wilson's magazines are under sprung. What I question is that while using the same mags, but a different pistol, I get great performance. I've shot a second Colt 1991A1, a Colt Series 70, a Wilson CQB and a LBC TRSpecial with these magazines and haven't had a failure to feed or lockback. I'm hesitant to change out the springs in these magazines when they perform perfectly with other 1911's.

What I may do is bite the bullet and accept the fact that this pistol is mag sensitive. I'll go back to the slidestop that worked with Metalform mags and I'll use only MF mags in this 1991. Thanks.

 

[1911Tuner]

Different Guns

Howdy riverdog,

One thing that I forgot to mention is that a heavy recoil spring will
aggravate the situation. Some pistols seem to run fine when they're
slightly oversprung and some don't. You may find that yours will
do okay with the Wilson magazines with a standard 16-pound spring.

Most new 5-inch Colts have a 14-pound spring as tested, even though
specs call for 16, and I've never tested the recoil spring in a new Commander that checked at more than 16.5 pounds. Spec calls for
18 pounds for the Commander variants. The only reason that I can come
up with is that they're making the pistols less sensitive to magazine timing.

Try a 16-pound spring and see if the problem changes. It may be just that simple.

Keep us posted.

Tuner

 

[riverdog]

Thanks Tuner. This issue originally came up while using the factory spring, but I'll order up a new Wolff 16# and try that to see if it changes anything. I will also try polishing the rear of the Wilson slidestop to see if that will get it to function. Accepting the problem will be a last resort. The biggest problem with determining a true cause is the occasionalness of the problem. 80% of the time it works fine. That other 20% comprises a lot of malfunctions.

 

[1911Tuner]

80/20

Ahhh...Now we're gettin' somewhere. The problem is on the ragged edge
of not happening. That suggests the first suspicion...the magazine spring
is almost up to the task, but not quite. Call Wilson Combat and see if
they'll send you fresh springs for those magazines. If you're using the
8-rounders, you may find that getting the spring and follower to convert
them to 7 rounds will probably cure the last round escape that you're having.


If Wolff makes an 11-pound spring that will mate to the Wilson-Rogers
follower, get one. Since I don't use Wilson magazines, my experience
with them is limited.

Luck to ya!

Tuner

 

[riverdog]

I'll call Wilson tomorrow. You're right the 80/20 mix does make it seem that it wants to work, just misses every now and then. Works fine with the mags that came with LBC, so maybe it is the Wilson 47D's. Seems that I've gone full circle on this one. Thanks again.

 

[riverdog]

Tuner,
Looking through my small assortment of 1911 magazines, in addition to the Wilsons, I have a few Colt Mags with the classic flat follower and a few Metalform mags with round followers as well as some generic USGI mags. I'm going to reinstall the original slidestop (a Colt that's been dimpled) and try it with these other magazines. If it runs then I have another data point and the Colt's problem will be sorta kinda fixed. For now I'm putting the Wilson slidestop back in my spare parts drawer. Film at 11.