Slide Locks Back Early

[TunnelRat]

Hi all,
I don't run into this malfunction much, in fact I don't know if I have had it happen before.

I was shooting my S&W M&P 9c. I had run 50 rds of Blazer aluminum with no issues. I decided to shoot off my carry ammo as I hadn't run any hollowpoints through it yet. There were no hangups at all. However when the slide locked back I went down to check my target. When I came back I noticed there was actually still one round left in the magazine. I was shooting 124 gr +P Gold Dots, short barrel.

What might cause this to happen? Maybe I pushed up on the slide release by accident? It is a stout load out of the M&P 9c, can really feel that slide moving fast, but it felt very controllable. I only had the one magazine so I couldn't run more Gold Dots to see if it happened again. It might just be a fluke but I didn't know if there was something I should check.

-TR

 

[claymore1500]

In all of the guns I know of, the slide lock is pushed up by the mag follower, when the mag is empty.

If the slide locked back with one in the magazine, then I would have to assume you pushed the lever up inadvertently, or the round may have started to chamber, but got hung up on the ramp, holding the slide back.

I would be inclined to look into the latter, as it may prove to be a problem in the future.

 

[Wreck-n-Crew]

Ive seen this ALOT. Hold your Thumb on the trigger hand down with your thumb from the brace hand right on the thumbnail.

So if you are shooting Right handed hold down your right thumb with the left thumb. Shouldn't affect your grip or accuracy on the 9c compact.

Because of the shorter grip, people tend to try to get high enough on it to maybe slide in a pinky or get a better grip. After shooting a few they loosen the grip on the recoil and the thumb hits it.

 

[TunnelRat]

The round definitely hadn't started to chamber, it was completely to the rear of the magazine.

It is possible that my thumbs forward grip led to the issue. I've never had this issue with any standard pressure ammo, so I'm willing to believe the more powerful ammo combined with my somewhat faster shooting could have caused my thumb to move to the slide release.

I will get back out and fire the rest of that box and see what happens ASAP.

 

[Wreck-n-Crew]

Should be fine...but yeah...the compacts of all kinds have people adjusting their grip.

I have had to do the thumb over thumb before because the slide would rum a blister or cut me between the thumb and forefinger.

Anyway the placement of the 9c slide lock is perfect for slide locking during fire.
I don't even call it a shortcoming of the design if you can adjust.

 

[Walt Sherrill]

What might cause this to happen? Maybe I pushed up on the slide release by accident? It is a stout load out of the M&P 9c, can really feel that slide moving fast, but it felt very controllable. I only had the one magazine so I couldn't run more Gold Dots to see if it happened again. It might just be a fluke but I didn't know if there was something I should check.

Other possibilities, although these are less likely, are 1) a slightly out-of-spec slide stop, or 2) slightly out-of-spec (too long OAL) ammo.

I've seen both in a couple of guns. In the case of the slide stop, check the tab where it is pressed up by the follower. If you see copper smudges on the slide stop, that might be it. This wouldn't necessarily be a problem with all ammo, but it could happen if the ammo is pushing the OAL range.

Check also that the ammo you're shooting isn't just a hair longer than usual.

 

[TunnelRat]

Hmm, good to know. Thanks!

 

[James K]

Another possibility is that the bullet may be pushing up on the magazine stop. That can happen when the ogive of the bullet is a different shape than standard (like some 147 grain bullets or some home cast bullets). Note that most causes can happen with any round; if the condition regularly happens with the next to last round, the magazine follower itself, or the position of the magazine in the magazine well is probably to blame.

Jim