I went to the range recently with my nearly 15 year old Colt 1991A1 (I bought it in 1992) and fired around 100 rounds of S&B ball. In the past it's always functioned perfectly. I only used a single magazine in my recent range session. During my shooting session I noticed that the gun was not locking back upon firing the last round most of the time. Once, upon inserting the magazine freshly reloaded, the slide fell on its own without me pressing the slide release. This was a little upsetting. The only thing ever done to this gun is that I recently replaced the factory recoil spring with a Wolff "type B" from Brownells. Anybody have any ideas on what's the problem?
The usual problem is that the slide stop isn't being fully engaged for some reason.
With the slide stop just barely engaged, when you insert the magazine, the stop is "jarring off" and allowing the slide to close.
First, inspect your slide stop and the notch in the frame it engages.
Check for burrs on the slide notch, and for free movement of the slide stop.
Check the slide notch for excessive wear that may cause the stop to fail to hold.
Check to insure that if you manually push the stop up, it fully engages the notch in the slide, and prevents it from closing.
Next, inspect your magazine. The "probable" cause is a magazine that's failing to push the stop up fully.
This can be a dirty or worn magazine.
DB wrote:
I went to the range recently with my nearly 15 year old Colt 1991A1 (I
bought it in 1992) and fired around 100 rounds of S&B ball. In the past it's
always functioned perfectly. I only used a single magazine in my recent range
session.
Aha! Two clues in the first paragraph!
1... Older pistol, w/perfect function before the last session.
Possible weak plunger spring or worn front pin.
2... One magazine used during the session.
Possible magazine problem. Specifically, weak spring or incorrect angle on the shelf that engages the slidestop lug, causing the stop to partially engage.
Thanks guys... You've both given me some things to check out. I knew I should have taken more than one magazine with me to the range... That would have ruled in or out the magazine being the problem. I'll check the parts you guys suggested when I get home from work tonight. Thanks again for the good suggestions! Have a great weekend!
Really? The slide isn't supposed to slam home automatically when a fresh mag is inserted with the proper force? My SA 1911 GI chambers when I give the mag a little slap. Same thing for my Sig 228. I *assumed* it was because both of these designs were military issue and they were designed to chamber automatically for efficiency in combat. None of my non-issued guns do this no matter how hard you slap 'em.