I have a Glock 17.  I have over seven high cap factory LE mags for it and none of them will hold the slide open on the last shot.

Is this a Glock quirk?
Is something wrong with my particular Glock?
Is something wrong with all seven magazines?

I've had this G17 for less than a year so I don't have a ton of experience with it.

Thanks.

Sounds like the magazine followers do not have sufficient spring pressure to push up on the slide stop lever, allowing the slide to be locked to the rear.

Then again, someone may have taken it apart and not put it back together properly.

Does the slide stop lever operate properly?

Have you gone to a gun shop (or taken a friends functioning mag) and taken your unloaded weapon there and insterted the new magazine into the unloaded weapon, with the slide forward, retract the slide and see if the new mag will lock the slide to the rear?

Have you tried your mags on another gun?

Your results in these trials will determine the problem.

Ed
(Who just happens to be a certified Glock armorer)

will it lock back manually, with or without a empty mag inserted?

It's hard to imagine that ALL of your magazines are screwed up.  I'd take a close look at the slide stop lever.  Check that it is not damaged, or installed improperly.  It should be a fairly easy fix.  Here is a link to the disassembly/assembly  instructions.

Linky


Good luck.

Quoted: Glock also sells non-hold open mags.  Have these mags ever held the slide back?  Maybe you got some of the Non-hold open ones.

Do you have a link to such mags? I've never heard of them.

You might be inadvertently hitting the slide-stop with you thumbs when firing.  Is your handhold "thumbs-high"?

Quoted: Quoted: Glock also sells non-hold open mags.  Have these mags ever held the slide back?  Maybe you got some of the Non-hold open ones. Do you have a link to such mags? I've never heard of them.

Neither has anyone else.

I think DigDug may be talking about the non drop free mags that Glock makes.  They are very popular with European LE because they have to retain their mags 100%.

I have not heard of a non-hold open mag either.  

I'll give the slide stop a +1 for the first thing to inspect.  I just replaced one of mine.

Im  knew to glocks,but think what he meant was  their old mags arent drop free,like the newer ones.

For the guy having lock up problems,slide stop  or binding spring, probably isnt installed correctly.

Also, you hand may be big enough "hand" to where you keep bumping slide release?

Spring?

Let us know when you find out.

TG

TexasGunman has a good point, is there any chance that you are accidently holding down the slide stop while you are shooting?  Try shooting and making sure that your hand/thumbs are not inadvertently touching the slide stop.

Does the slide hold open if you manually lock it back?