Premature Lockback of Slide

[Eager]

Yesterday at practice I got a few cases of the slide locking back with rounds still in the mag.  Today at the USPSA match it happened once.  

I don't think my fingers touch the slide catch while shooting (I'm not totally sure though, I'll have to check that at cleaning time).  Anyway, asuming it was not finger caused, what caused this and what can I do about it.  My times are slow enough already without this, so I need the help.  My accuracy is good though, thanks to the 85 Combat and I don't have any other problems, but maybe a little better trigger would help times some too.

[Walt-Sherrill]

The most COMMON causes of this problem is:

1) weak mag springs.  (Weak mag springs allow the top round to slide around a bit as the slide slams forward, allowing it, in the firing cycle, to nudge the slide stop, allowing the slide to lock back.)

2) Out of spec. slide stop.  (Not likely if its a NEW event.)

3) Out of spec. ammo or ammo with a different bullet shape.

If your mag springs have some life on them, but you have some newer mags, see if the problem is happening on the same mag.  (Mark the mags to keep them "distinct.")

Also check the slide stop to see if you seem marks from the bullet nudging the stop.

We've seen some relatively new mags from CZ with weak springs in the past year.  5% extra strength mag springs from Wolff might be the solution.

[Tangram 37]

Check the slide stop spring for proper tension.  Does the slide stop "snap" up into place?

[Walt-Sherrill]

I started to mention the slide stop spring, but was reminded by others here, the  last time this subject came up, that a weak or mispositioned slide stop spring usually causes the slide NOT to lock back.  

But, if the spring is out of position or weak, it may allow the slide stop to move round during the normal firing cycle.  

A possibility to consider if nothing else solves the problem...

[Tangram 37]

Be as that may, not locking back....  From personal experience I know a bent spring can cause premature lock back.  No ranking on my part of the likely hood of that happening as I seem to have unique things go astray.