MP-Pistol Forum banner

Failure to lock slide open+initial impressions

1648 Views 5 Replies 4 Participants Last post by  Arizona Smithshooter
Went to the indoor range Saturday, put 200 rounds of Winchester White box from Wal-mart thru the M&P 9mm. (Forgot bullet wt)

Had several (5-6) instances of the last round not locking the slide open, but allowing it to close on an empty chamber.

Anybody else have similar experience with a new M&P and new magazines?

Could it be "weak" loads in WWB? Could it be that the gun simply need some breaking in? Magazines need some breaking in?

Apart from that, I found it incredibly accurate. It points so naturally it's almost spooky. Took a little while to get used to the trigger, but that is to be expected.
1 - 6 of 6 Posts
Is there any chance your thumb was resting on the slide stop, keeping it from activating?

I have 2 M&P 9's with over 3000 rounds thru them, combined, and have not had this problem with either one.

I have had some problems with the slide dropping by itself, without chambering a round, when I perform a reload. I was in the same squad with Ernie Langdon at IDPA Nationals and he diagnosed it as a shooter induced problem. He said I am slamming the magazine in too hard and causing the top round in the downloaded magazine (10 rds in a 17 rd mag) to bounce down just when the slide goes forward and it fails to pick up the first round.

Could be I suppose...

I will have to check my grip and watch for this.

Does it happen with both magazines? It is the follower in the magazine that pushes up on the slide lock when the magazine is empty. Is the slide lock binding, does it move freely? Insert an empty mag and watch how the follower pushes up on the slide lock.
Likely you are hitting the slide release. I have the same problem with the extended slide releases if I use any insert other than the large grip insert. The large insert keeps my strong hand thumb just far enough away that I cannot hit it by accident.


Have you figured out what the problem was? Sure would like to hear an update...
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.