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10/18/2016 2:39:54 PM EDT
Took my Colt GCNM out today, shot 75 rounds of 230gr ball.

Twice, with two different mags and two different brands of ammo I experienced the following:

-Fire next to last round
-Slide locks to rear
-Last round from the mag is resting loose on top of the magazine, behind the chamber

The ammo (both 230gr FMJ):
Federal American Eagle
Speer Lawman

The Mags:
Colt 7rd, hybrid lips
Chip McCormick Shooting Star

Gun has less the 500 rounds through it. I doubt either mag is over 2,000.

I'm thinking weak mag springs, causing the mag to lose control of the last round under recoil - kinda surprised to get that with the dimpled follower though. Anything else I should check out?
10/18/2016 4:06:45 PM EDT
[#1]
If those are not the only mags you have, try another. Sounds more like a mag problem than anything else.
90% of 1911 malfunctions are mag related.
10/18/2016 4:17:14 PM EDT
[#2]
Quote History
Quoted:
If those are not the only mags you have, try another. Sounds more like a mag problem than anything else.
90% of 1911 malfunctions are mag related.
View Quote


Forgot to mention that - had two other mags with me, Wilson ETM's, no issues.

10/18/2016 4:37:12 PM EDT
[#3]
What weight of recoil spring is installed?
10/18/2016 5:45:54 PM EDT
[#4]
Quote History
Quoted:
What weight of recoil spring is installed?
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The Colt standard, 16lb aren't they?

(It's not the green marked light spring)
10/18/2016 6:10:55 PM EDT
[#5]
Sounds like inertia feed - magazine and or extractor tension issue-
10/18/2016 8:03:40 PM EDT
[#6]
Quote History
Quoted:


The Colt standard, 16lb aren't they?

(It's not the green marked light spring)
View Quote View All Quotes
View All Quotes
Quote History
Quoted:
Quoted:
What weight of recoil spring is installed?


The Colt standard, 16lb aren't they?

(It's not the green marked light spring)


Generally.  I understand the GCs came with a 14# spring. My theory is that the spring is allowing the slide to give the frame a pretty good smack at the end of its travel, jarring the last round loose.  Do the followers have dimples?
10/18/2016 8:47:04 PM EDT
[#7]
Quote History
Quoted:


Generally.  I understand the GCs came with a 14# spring. My theory is that the spring is allowing the slide to give the frame a pretty good smack at the end of its travel, jarring the last round loose.  Do the followers have dimples?
View Quote View All Quotes
View All Quotes
Quote History
Quoted:
Quoted:
Quoted:
What weight of recoil spring is installed?


The Colt standard, 16lb aren't they?

(It's not the green marked light spring)


Generally.  I understand the GCs came with a 14# spring. My theory is that the spring is allowing the slide to give the frame a pretty good smack at the end of its travel, jarring the last round loose.  Do the followers have dimples?


The new ones come with two recoil springs, a standard Gov't Model spring and a lighter spring (I've heard both 12 and 14 pound) with a green marking. Regular one is what's in it. I'll probably replace it with a Wolff  anyways though, as your theory is sound. Maybe an EGW firing pin stop at some point too.

The Colt mag does have a dimple, but upon closer inspection tonight it appears one of the feed lips is flared outwards, so I'm betting that was a contributing factor. No dimple on the CM mag.