Smith & Wesson Forum

Go Back   Smith & Wesson Forum > Smith & Wesson Semi-Automatic Pistols > Smith & Wesson M&P Pistols
o

Notices

Smith & Wesson M&P Pistols All Variants of the Smith & Wesson M&P Auto Pistols


Reply
 
Thread Tools Display Modes
  #1  
Old 02-21-2020, 10:59 PM
scattershot's Avatar
scattershot scattershot is offline
Member
Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine  
Join Date: Oct 2008
Location: Denver, CO
Posts: 1,812
Likes: 166
Liked 977 Times in 489 Posts
Default Slide locks back with round in magazine

I have a M&P40c (Mod1). Lately I have noticed that the slide locks back With the last round still in the magazine. Any suggestions? By the way, this pistol rides in my truck and doesn't get shot much. Could having the mag loaded weaken the spring and cause that?
Reply With Quote
  #2  
Old 02-21-2020, 11:52 PM
Execpro Execpro is offline
Member
Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine  
Join Date: Apr 2016
Location: Ohio
Posts: 649
Likes: 5,055
Liked 656 Times in 339 Posts
Default

Never heard that one before! Usually a weak spring will NOT lock the slide back. Option 1: I suggest with limited info, that you take the gun/mag down and give them both a GOOD cleaning/lube where appropriate. Put in NEW ammo and shoot it again.
Option 2: Stay tuned until someone far smarter than me comes along with different options/suggestions/answers.

Be SAFE and Shoot Often!
Reply With Quote
  #3  
Old 02-22-2020, 12:47 AM
Funflyer's Avatar
Funflyer Funflyer is offline
Member
Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine  
Join Date: Sep 2016
Location: Central Arizona
Posts: 1,031
Likes: 1,096
Liked 1,742 Times in 585 Posts
Default

What ammo are you using in it? Could be the mag spring is weak enough to let the round move forward just enough so the bullet makes contact with the slide stop.
Reply With Quote
  #4  
Old 02-22-2020, 01:24 AM
merl67 merl67 is offline
SWCA Member
Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine  
Join Date: Apr 2011
Location: Northern Middle Tennessee
Posts: 2,898
Likes: 3,413
Liked 4,084 Times in 1,449 Posts
Default

I had a Taurus TCP 380 that would intermittently do this with a loaded mag it was random might be 6 rounds in the mag might be two. The slide lock protruded into the gun just a bit too much, and a round coming up would occasionally hit it locking the slide back. A little file work on the stop cured it
__________________
Randy
Reply With Quote
  #5  
Old 02-22-2020, 03:40 AM
s2harry's Avatar
s2harry s2harry is offline
Member
Slide locks back with round in magazine Slide locks back with round in magazine  
Join Date: Feb 2009
Location: Commifornia
Posts: 226
Likes: 83
Liked 108 Times in 59 Posts
Default

Make sure the bullet is not hitting the slide lock on the inside of the slide. Maybe youcan file the lock off a bit or use pointy bullets. Taking to a gunsmith is better than asking questions on here...
__________________
US ARMY
Viet Nam 70-71

Last edited by s2harry; 02-22-2020 at 03:42 AM.
Reply With Quote
  #6  
Old 02-22-2020, 03:58 AM
jake1945's Avatar
jake1945 jake1945 is offline
Member
Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine  
Join Date: Dec 2011
Location: S.E. Iowa
Posts: 672
Likes: 286
Liked 726 Times in 304 Posts
Default

I had that happen with my 1911 45acp. I was shooting reloads and occasionally the slide would lock open. Cause was bullet was not seated deep enough and tripped the slide lock. Seating the bullets a bit deeper was the fix.
Reply With Quote
  #7  
Old 02-22-2020, 10:51 AM
RobzGuns's Avatar
RobzGuns RobzGuns is offline
US Veteran
Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine  
Join Date: May 2012
Location: Texas
Posts: 2,878
Likes: 1,668
Liked 2,344 Times in 1,110 Posts
Default

Springs usually don't weaken from lack of use. Repeated use is what weakens springs.

A majority of the time that your situation occurs (as well as the slide NOT staying open after the last shot), one of the shooter's thumbs is nudging against the slide lock lever. When shooting, it doesn't take much force to nudge the lever up (or down)

Everyone swears that their thumbs are nowhere near the lever, but the next time this happens, **Freeze** and without moving your hands, check your grip. You may find that one of your thumbs is against the lever. Been there... Done that!
Reply With Quote
The Following 4 Users Like Post:
  #8  
Old 02-22-2020, 11:23 AM
scattershot's Avatar
scattershot scattershot is offline
Member
Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine Slide locks back with round in magazine  
Join Date: Oct 2008
Location: Denver, CO
Posts: 1,812
Likes: 166
Liked 977 Times in 489 Posts
Default

Thanks for the insight, guys. Factory Federal hollowpoints live in this gun, but I was shooting some handloads, too. The inadvertent pressure on the slide stop lever may be the culprit, I’ll check that next time out, thanks.
Reply With Quote
The Following User Likes This Post:
Reply

Thread Tools
Display Modes

Posting Rules
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Shield 9mm slide automatically locks back when racked back sermy01 Smith & Wesson M&P Pistols 16 07-07-2022 03:56 PM
M&P 40 Slide locks with rounds in magazine. SoldierCat12 Smith & Wesson M&P Pistols 5 12-22-2015 07:50 PM
last round in mag and slide locks back ussoldier1984 Smith & Wesson M&P Pistols 2 06-09-2015 01:36 PM
s&w 22a locks back with last round still in mag the grey ghost Smith & Wesson Semi-Auto Pistols 6 07-23-2012 09:26 PM
Slide locks open with round in mag- M&P 9C Sparx Smith & Wesson M&P Pistols 9 07-07-2011 07:06 PM

Powered by vBadvanced CMPS v3.2.3
smith-wessonforum.com tested by Norton Internet Security smith-wessonforum.com tested by McAfee Internet Security

All times are GMT -4. The time now is 08:00 AM.


Smith-WessonForum.com is not affiliated with Smith & Wesson Holding Corporation (NASDAQ Global Select: SWHC)