• This Forum is for adults 18 years of age or over. By continuing to use this Forum you are confirming that you are 18 or older. No content shall be viewed by any person under 18 in California.

1911 slide failure to lock open on an empty magazine - new cause

This subject has been addressed many times and solutions include such things as replacing the magazine spring, bending the engagement tab on the follower outward, replacing the slide stop, using hotter ammo, replacing the recoil spring with a lighter one, and others.

Today I discovered a new-to-me reason for this kind of malfunction.

I had multiple failures-to-lock-open with three specific magazines. I chalked it up to cold weather and/or a weak powder charge. But this just didn't make sense to me since this pistol has had thousands of rounds through it with many magazine brands and has always run 100%.

When I got home I disassembled the three problem mags and remembered this was their first trip to the range. I put the followers back in and did my usual teeter totter test which they all passed. Then I put the mag springs back in with just enough tension to provide some resistance to the follower. I pushed each follower down and slowly let the springs push them back up and each follower got stuck just before coming all the way up into contact with the feedlips.

After a few more diagnosics I determined there was a burr left over from the manufacturing process on the inside surface of each mag tube in just the right place to prevent the follower from coming into contact with the slide stop lobe. This did not affect the feeding of the last round in the mags.

The fix was removing the burrs. Another trip to the range and the mags ran faultlessly.

The arrows in the pictures below point to the spot where the burrs occurred (inside the mag body).

AJBUG7O.gif


JBqnp7f.gif



Here's some more detail to show where the burr occurred and how it interacted with the follower.

"A" and "B" in the picture below are pointing at different areas of the tab on the mag follower that makes contact with the slide stop lobe to push it up after the last round in the magazine is sent down range.

"A" indicates the very top surface of that tab. This is what actually contacts the underside of the slide stop lobe. If you look very carefully, you can see this surface looks a little different than the rest of the follower. That's because the follower wasn't cleaned after shooting and the powder residue has been worn away in that spot because of repeated contact with the slide stop lobe. This picture was taken after I'd gotten rid of the burr and the follower was now doing its job of holding the slide open.

"B" indicates the very edge of the tab where it had been running into the burr. Once again, a close examination will reveal a very small area where the bluing had been worn away by the burr.

5OkzP2R.gif



"C" in the picture below shows the exact spot where the burr and the follower met. When this happened the follower would stick which meant the follower tab couldn't push the slide stop up to engage the slide. Note how the follower is not fully up against the feedlips.

The follower had not been stopped by the burr until after the last round had been chambered. At that time the follower rose up in the tube but was still being slightly depressed by the disconnector rail. When the slide moved rearward and the disconnector rail was no longer depressing the follower, the follower moved up enough to hit the burr which stopped it in the position shown in the picture.

TiN08II.gif
 
Great work. Most of the time the cause is bouncing the slide stop from too weak of a recoil spring or limp wrist but thats a good catch
 
Brownings design often copied but never duplicated. Good catch on your part as they require attention to every detail. When they run, they run great. We have seen 1911's sent to us where some jack leg 1991 smith advertising on the net monkey it up, they call us : )
 

Upgrades & Donations

This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.


Click Upgrade Membership Button ABOVE to get Gold or Silver Status.

You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.


To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.

Forum statistics

Threads
165,534
Messages
2,198,066
Members
78,961
Latest member
Nicklm
Back
Top