M&P9C: no slidelock with empty mag

[s0nspark]

I took my new M&P9C to the range today for the first time and noticed that, through the one mag I had with me, the slide did not lock back after the last round 8 out of 10 times... This was a brand new mag, as well.

Any suggestions as to how to isolate the problem? My first thought is blame the mag (mag spring or follower), but I'm a n00b with this stuff :-D

I plan to call S&W, but I'd hate to have to send the gun back since it is my only one at the moment, especially if the mag is to blame.

Thanks!

 

[shawn mccarver]

I took my new M&P9C to the range today for the first time and noticed that, through the one mag I had with me, the slide did not lock back after the last round 8 out of 10 times... This was a brand new mag, as well.

Any suggestions as to how to isolate the problem? My first thought is blame the mag (mag spring or follower), but I'm a n00b with this stuff :-D

I plan to call S&W, but I'd hate to have to send the gun back since it is my only one at the moment, especially if the mag is to blame.

Thanks!

These are shipped with two magazines. Test the other.

If you only got one, then the seller "appropriated" the extra magazine. I suppose that is ok if you were told and got a price reduction - the distirbutor CDNN has been doing this for years. But, if you were not told, or the seller sold you a brand new gun without the included second magazine, then you were, in my opinion, cheated.

 

[s0nspark]

These are shipped with two magazines. Test the other.

If you only got one, then the seller "appropriated" the extra magazine. I suppose that is ok if you were told and got a price reduction - the distirbutor CDNN has been doing this for years. But, if you were not told, or the seller sold you a brand new gun without the included second magazine, then you were, in my opinion, cheated.

Oh, I got two... the other was just loaded with SD ammo and left in my car I'm definitely going to rotate the mag in question out and try the others (just got my two freebies in the mail this afternoon) to rule out an issue with the gun itself...

Thanks!

 

[handgunner356]

As long as you can pull the slide back and have it lock with a empty mag in place, it's probably not a mag problem. A couple of things could be is being new/tight gun the slide isn't recoiling far enough or the load you're shooting is on the light side not sending the slide far enough to the rear to catch. I'd probably give it 2-300rds and several different loads before getting excited about sending it in. It's a good idea to mark your mags also to tell if one is giving you a problem or not.

 

[s0nspark]

As long as you can pull the slide back and have it lock with a empty mag in place, it's probably not a mag problem. A couple of things could be is being new/tight gun the slide isn't recoiling far enough or the load you're shooting is on the light side not sending the slide far enough to the rear to catch. I'd probably give it 2-300rds and several different loads before getting excited about sending it in. It's a good idea to mark your mags also to tell if one is giving you a problem or not.

Good points... and the gun does lock back when pulling the slide back so I am now thinking that it may just be a new/tight recoil spring... I was shooting Winchester White Box ammo and I haven't had trouble with that out of other guns - I don't think it is considered a particularly light load.

I am going to take your advice and just put more/other rounds through it next week. I have some DoubleTap Barnes TAC-XP and some Federal American Eagle FMJ plus more WWB I can run through it and try my other 9C/9FS mags to boot and we'll see where that gets me.

Thanks!

 

[ken158]

Shoot some different ammo - WW white box is sometimes weak... it will function but not bring the slide back far enough on the last round to lock back.

 

[s0nspark]

Shoot some different ammo - WW white box is sometimes weak... it will function but not bring the slide back far enough on the last round to lock back.

Really? Hmm ... I'll definitely try some other stuff then. This being a brand new pistol, I'm sure it has more work to do anyway with the new recoil spring...

Thanks!

Any recommendations as to something other than WWB that is more consistent?

 

[blastfact]

Really? Hmm ... I'll definitely try some other stuff then. This being a brand new pistol, I'm sure it has more work to do anyway with the new recoil spring...

Thanks!

Any recommendations as to something other than WWB that is more consistent?

It's all retail junk now days. The best retail junk I've found to date is Win Nato 124gr FMJ. It's a tad on the hot side. But I've never found a round out of physical spec.

 

[SWAT Lt.]

I think it is unlikely that it is a mag problem. Test the empty mags by inserting them into the gun and pulling the slide back. If it locks open it's GTG. More likely it is a shooter induced problem. Many times people (especially new shooters) will have a shooting grip and their thumb will be contacting the slide stop preventing it for operating properly. When you test your mags, and next time you go shooting, be aware that your thums(s) are not close to the slide stop while operating the firearm. Good luck, and enjoy your new M&P!

 

[s0nspark]

More likely it is a shooter induced problem. Many times people (especially new shooters) will have a shooting grip and their thumb will be contacting the slide stop preventing it for operating properly.

Well, I doubt that is the issue, simply because I have long fingers and they do not fall near the slide stop when I grip the gun. I haven't had this issue when I've shot my step-dad's M&P9C either, so I'm thinking it is a combo of brand new recoil spring and maybe weak ammo...

I'll definitely look out for this on my next range trip, though.

Cheers,
Tim

 

[s0nspark]

*sigh* I should have kept my mouth shut until after I went back :-/

I tried 3 other mags and the mag I used previously, shooting a single round of AE FMJ. and each mag locked the slide back just fine... I was happy!

However...

I noticed once I started shooting that in making sure to place my off-hand thumb on the frame just forward of the takedown lever, that tended to push the thumb of my strong hand up in the vicinity of the slide stop lever. I made a point to keep my grip down but I had a few more instances of no slidelock while shooting, but this was again using WWB. Very frustrating...

I need to work on getting my grip locked in, given that this is a new gun. The bad part is that I have not had this problem with other pistols - but that was before I started using the thumbs-forward grip...

Ammo may still be a factor but I don't think the gun or mags are to blame. Thanks much for nudging me out of "blame the gear" mode

 

[s0nspark]

... and a small follow-up ...

I am surprised at how little pressure on the slide stop is needed to keep the gun from locking back. I mean, just lightly resting my thumb on it and pulling the slide rearward with an empty mag can cause it to fail to lock back...

Is that normal?

 

[handgunner356]

Sounds normal, take the slide off and stick a empty mag in the frame and you can see how little pressure raises the slide stop lever.

 

[s0nspark]

Sounds normal, take the slide off and stick a empty mag in the frame and you can see how little pressure raises the slide stop lever.

All the more reason for me to be more careful! *sheepish*

I did notice that I can rest my off-hand thumb on the trigger guard instead (there is a little indentation in the frame at the top of the left-hand side of the trigger guard perhaps for that very purpose) so I'll focus on doing that and see how things go...

Thanks for all the feedback!

 

[SWAT Lt.]

I'm glad you found out what the problem was without having to return your gun. I'm thinking about buying a 9c myself.