M&P .40c slide locked back but mag was not empty

[ussoldier1984]

Took my 40c to the range yesterday and put 200 rounds through it. Twice out of the 200 rounds my slide locked back but the mag was not empty. It could of been my hand placement but if it wasn't what else could of caused it?

 

[RobzGuns]

The only thing that could cause the slide to lock back, is for something to move the lever upward. Normally, the only 2 things that would cause the lever to move would be either the Mag Follower, or a finger.

With Compacts and Subcompacts, It's very easy for one's thumb to inadvertently put upward pressure on the lever during recoil. It's an easy cause to overlook.

Lately, after 3yrs of shooting my Shield, I've had just the opposite problem with my thumb, that popped up out of nowhere... I'm periodically putting downward pressure on the lever, causing mine NOT to lock back when empty.
Go figure!

 

[ussoldier1984]

The only thing that could cause the slide to lock back, is for something to move the lever upward. Normally, the only 2 things that would cause the lever to move would be either the Mag Follower, or a finger.

With Compacts and Subcompacts, It's very easy for one's thumb to inadvertently put upward pressure on the lever during recoil. It's an easy cause to overlook.

Lately, after 3yrs of shooting my Shield, I've had just the opposite problem with my thumb, that popped up out of nowhere... I'm periodically putting downward pressure on the lever, causing mine NOT to lock back when empty.
Go figure!

LOL considering it only happened twice with 200 rounds. This is my first compact and real polymer frame. Next time I go to the range I will try to be more aware of my thumb placement. Just wanted to know if it wasn't my thumb then what else could of caused it.

 

[ca survivor]

you answered your own question " could of been my hand placement "

 

[Rastoff]

Yes, can certainly be caused by thumb placement.

The goal is to have relaxed thumbs. This is not easy, but something to shoot for. If you can relax your thumbs, this will never be a problem.

 

[Johnmuratore]

I've had this happen a couple of times with all my compacts and its always been thumb placement of my support hand. Lately I've adopted a more downward and full wrap of my support hand and it hasn't happened.
Also had the slide NOT lock back on the last round and it was the same problem.

 

[TimmyRay]

No need to worry it's more than likely your finger placement with my shield if I grip too high up under the slide release it would lock the slide back and if I gripped to high up tword the top it would prevent it from locking back. Also sometimes occasionally if a round was not seated properly in the magazine it would lock my slide back. Those are really the only two senerios I can think of.

 

[Pete1971]

I've had this exact problem, my solution was try a different mag and it worked, so out of 4 mag's one has this issue which I marked and try again periodicly and same problem, the others run just fine and there all factory mags