"Double Load"?

[Steely Dan]

Yesterday, I took my CCW Class. My pistol is a SW M&p .40. While on the range, I had something that happened and I assume was my fault and not the pistol. We were preparing for our third round of firing. My slide was locked open. We were instructed to load magazine and prepare to fire when the instructor gave the command. I slide the magazine in the gun and the slide automatically slid shut. But it did not go all the way. One bullet went in at angle and the bullet below it in the mag also was angled to go in. I raised my free hand and kept the barrel down range and waited for the instructor to come to me. He told me it was a double load. We disengaged the mag and cycled the bullet out. Reinserted the mag, slide and chambered the round. No more issues. When I slammed the mag into the gun, is it supposed to automatically activate the slide our do I activate it? I am new to autos and want to make sure I am not getting bad habits early. Any advice would be appreciated. SD

 

[MP22]

Slamming the mag in the gun should not close the slide. You can release the slide manually. That is definitely a safety issue.

 

[vigil617]

In my limited experience with semi-autos, the only time this has happened was with my full-size M&P 40, and it only occurred once, and it did not "double load," only chamber a single round properly.

I have read on this Forum, though, that slamming a magazine home forcefully with the slide open will sometimes activate the slide, chambering the next round in the magazine. My impression is that this is a slight malfunction of the pistol, and that normally you should have to depress the slide release in order to make an open slide go forward.

Some of the more experienced hands on the Forum can shed more light on this for you, I'm sure. I have learned an awful lot from them in the few weeks since I found the Forum.

In the meantime, good luck in getting your CCW.

 

[Houdini1953]

What you experienced is what is called auto forward, and usually happens with some M&P's. One of my 40's does it almost always as well as my 9mm, and one of my 45's but not my Shield40.

The best corrective action is to first clean your weapon paying particular attention to the feed ramp of your gun. When new there is some factory oils and other gunk that should be removed for flawless use of the weapon and I believe all owner's manuals state that you should first clean your weapon before you fire it for the first time!

The feed ramp should be clean and shiny and make sure that you clean and lubricate the 7 points as specified in the owners manual for your weapon which is mostly the slide and slide rails! Clean your gun and try it again and there should be no problems.

 

[Steely Dan]

Thanks for the responses. My gun was clean. I cleaned it before I ever shot it and I always clean it when I am finished shooting. When the gun jammed, one of the instructors told me from that point forward, just load the mag and rack the slide. I have never loaded the pistol like this before. When we were in class, we went over range rules and it was protocol to stand with the slide locked open. From this point forward, I will not "slam the mag in" but rather insert it as I have before. Firm but not overdoing it. That being said, the more I shoot this pistol the more I like it. My groups were pretty good (probably because I had a range instructor right behind me). I look forward to getting better familiar with the MP.

 

[ImmaculateSludge]

very common with m&p pistols (Not the double feed part) you can fix it if you want to by stoning the back side of your slide catch at a 90 degree angle. I don't agree that this is really much of a safety issue as it isn't likely to cause an inadvertent discharge. Fix it or leave it... your call.

 

[vigil617]

Thanks for the responses. My gun was clean. I cleaned it before I ever shot it and I always clean it when I am finished shooting. When the gun jammed, one of the instructors told me from that point forward, just load the mag and rack the slide. I have never loaded the pistol like this before. When we were in class, we went over range rules and it was protocol to stand with the slide locked open. From this point forward, I will not "slam the mag in" but rather insert it as I have before. Firm but not overdoing it. That being said, the more I shoot this pistol the more I like it. My groups were pretty good (probably because I had a range instructor right behind me). I look forward to getting better familiar with the MP.

This is the way I do it myself with my full size 40 and my Shield 40. I rack the slide to move the first round from the magazine into the chamber. That way, I know when my weapon is loaded and ready to fire. I control when that happens. And that's the way I want it, even with all the internal safeties built into this fine weapon.

I hope you enjoy your 40 as much as I do mine. It is fun to shoot and dead-nuts accurate. I had a fullsize M&P 45 before this, and loved that one too, but decided for the time being to keep my calibers the same for ammo purposes. The M&P's are classics, in my opinion, and you will enjoy getting to know your weapon and its capabilities, and improving your own skill to match what the weapon is capable of doing. Have fun!

 

[S&WOkie]

I have never had that happen with my M&PC.

I never use my slide hold open lever as a slide release because I believe it contributes to the problem of the slide closing when slamming a mag home.

I always pull back and release the slide after inserting a magazine.

 

[lebomm]

Vigil617;
Where has that first round been if racking the slide moves it into the magazine? You probably mean "moving the first round into the chamber", right?

 

[Twoboxer]

I can't see how a double load could occur . . . unless you left a round chambered when you locked the slide open. If you did that, slamming the magazine enough to release the slide would attempt to load a second round. If you have some snap caps, you might try to reproduce the problem.

If you think about racking a "locked" slide, a small backward movement of the slide is often enough to release the lock and allow the slide to move forward. Slamming the magazine in hard enough, and perhaps with a little backward angle, can be enough to cause that small backward movement in some pistols.

 

[MichiganScott]

From the M&P Manual:

WARNING: DO NOT USE EXCESSIVE UPWARD FORCE
WHEN INSERTING A LOADED MAGAZINE INTO THE
PISTOL. EXCESSIVE UPWARD FORCE COULD CAUSE
THE SLIDE TO MOVE FORWARD, CHAMBERING A ROUND AND
MAKING THE PISTOL READY TO FIRE.

S&W knows it happens and apparently considers it operator error.

 

[cflshield]

I had the slide close when I loaded a magazine in my G19 on Saturday. It's the first time it's happened. I've read on the Glock forum that it is a daily occurance with some guns and some people actually prefer it to happen. I don't consider it a safety issue if you are following safety procedures such as keeping the weapon pointed down range or in a direction that's away from harm. I can't see how the gun would fire if you don't pull the trigger.

 

[vigil617]

Typo corrected; thanks, lebomm.

 

[George9]

It happens to a lot of auto.. Never slam the mag home when reloading with a open slide. There is a lot of generated pressure on the top round when the mag stops with all the rounds under it and there weight is expelled on that top round.. Slide mag in till you here it click. Use you thumb to seat it. You can check it if you want by pulling down on the butt plate to make sure it's secure.. As far as the double feed goes it's just that with the force of the mag being slammed home and a massive amount of energy is built up on the top round and slide release. The slide closes slower then it should or should I say the slide can't keep up with the amount of released enegry and round #2 is caught while the slide it still going forward trying to chamber the first round..
This occurs more in .22 cal pistols with over enthusiastic and inexperienced users. I don't think your gun is at falt here. It's all good your learning! George

 

[Steely Dan]

I don't think your gun is at falt here. It's all good your learning! George

You are correct. I do not fault the gun. I had never shot in that type of environment before, side by side with people who were much more experienced than I with a semi-auto. I guess the adreneline rush caused me to "slam it home" as my instructor said a little to much. Thanks for the feedback. I know it is a simple correction in my habits and not a faulty pistol.