View Full Version : M&P .40 malfunction
Took my M&P .40 to the range today and had a couple of buddies shoot it. Every shot these guys took was followed by a failure to feed! When I shot it, it ran smooth. I've put about 1000 rounds through this gun with zero malfunctions. These guys are firearms instructors so I assume they know what there doing and there not limp wristing the gun. My mags have Arredondo extensions with the original springs. The ammo used was Federal 155gr hollow points.
Anyone seen this happen before?
Wonder if I need longer mag springs?
Have you had issues with the magazines in question yourself? How about with stock magazines?
I have had bad experiences with aftermarket magazine extensions and as a result never use them. Not saying that this is the issue here but it is something to consider given that these guys are experienced shooters.
Forget to mention the mag extensions are fairly new. About 200 round through them. The previous 1000 rounds were with the original mags.
Change your magazine springs to extra power springs and your problem should go away.
Most mag extensions reduce reliability of the magazine even with extra power springs.
Just some food for thought.
Change your magazine springs to extra power springs and your problem should go away.
Most mag extensions reduce reliability of the magazine even with extra power springs.
Just some food for thought.
Thanks. Where can I find them?
Thanks. Where can I find them?
I swear I ordered mine from speedshooterspecialties.com but couldn't find them on their site. Brownell's has them:
http://www.brownells.com/.aspx/pid=32423/Product/S_W_M_P_HIGH_CAPACITY_EXTRA_POWER_MAGAZINE_SPRING
-Jax
I'm not big on thread resurrection but I was wondering if you were able to remedy your problem with extra power springs?
I picked up an Arredondo extension to try with my full size M&P9 and it has been 100% unreliable. When I load 22 rounds into the mag, the follower gets caught on the bottom of the mag body an the mag completely shits the bed. I have to dump the rounds out and try to pry the follower loose with a screwdriver.
I've tried contacting Arredondo to no avail, they won't get back to me :angry: Right now I have a completely worthless $18 piece of plastic.
Another suggestion I had is to pay careful attention to their grip. I thought I was having failure to feed problems, was about to go crazy trying different mags and making sure my feed ramp was clean, and then I realized that since I hold my support hand very high up on the frame, the meaty part of my thumb was actually pushing up on the slide catch. This resulted in random times when my slide would lock back.
I have since stippled my frame and put a thumb index spot on my frame. Since then I haven't had any issues whatsoever.
I figure if your friends are firearms instructors they may be using a very high support hand grip like I do, and could possibly cause this pseudo-malfunction. Hope this helps.
Just because they call themselves instructors doesn't mean they weren't limp wristing. A friend that I grew up with is an instructor for the Border Patrol, he doesn't even know how to sight in a rifle. He only knows how to repeat what he was told to say. Your tax dollars at work!
Speed shooters does have them on their website. $10 for one, $36.95 for 4. Brownells seems to be a bargain.
I'm not big on thread resurrection but I was wondering if you were able to remedy your problem with extra power springs?
I picked up an Arredondo extension to try with my full size M&P9 and it has been 100% unreliable. When I load 22 rounds into the mag, the follower gets caught on the bottom of the mag body an the mag completely shits the bed. I have to dump the rounds out and try to pry the follower loose with a screwdriver.
I've tried contacting Arredondo to no avail, they won't get back to me :angry: Right now I have a completely worthless $18 piece of plastic.
Smitty,
I understand the frustration with the Arrendondo extensions. There are quite a few HSLD shooters on here that use them without complication. There are others who have used them with absolute frustration. I've got a video somewhere of me at an advanced handgun class that shows me using my M&P9FS with the 2 Arrendondo extensions I brought with me that day and on film both of them are caught exploding off of the magazine. A shower of brass, plastic, and springs spewing from the botton of my handgun.
Now I understand this is not the particular problem you are being subjected to but I believe the cause maybe one in the same.
This problem you are having must first attempted to be fixed by trying out the power springs before attempting a fix. If you aren't using the extra power springs I suggest you try them before doing anything else.
If you are already then I believe the downfall of said extensions (for those people who are having issues with them is the retaining plate itself. I am referring to the L shaped piece of plastic that keeps the actual extension locked onto the mag body. It is thin, way too flexible and doesn't extend enough into the mag body to hold the extension firmly. In the past I have actually knocked the extension off during the tap portion of a tap/rack/bang drill.
Like I said the retaining plate is way too flimsy which I believe causes too much movement of the floorplate. When the floorplate moves the spring moves. When the spring moves the follower moves. That maybe just enough front to back movement to bind up the follower on the magazine wall.
Back in late 2010 I decided to try and fix this myself by replacing the factory retaining plate with a homemade version made of aluminum. I had some intial problems at first (the top portion of the endplate that actually enters the mag needed to be tapered more) but I've been using my 'fix' for the better half of two years now without a problem. The only downside is that it holds one less round than what Arrendondo states.
Here is a link to the thread I did on my fix:
https://www.m4carbine.net/showthread.php?t=67260
Hope this helps,
-Jax
Smitty,
I understand the frustration with the Arrendondo extensions. There are quite a few HSLD shooters on.....
Thank you for the reply. I remember reading your thread about the aluminum baseplate insert.
I'm going to try the extra power spring and see what results I get. As stubborn as I am, I've pried the follower out numerous times and tried the extension in different scenarios, trying to pinpoint the cause of the failure. I can consistently get the pistol to auto-forward 100% of the time without the baseplate sliding forward. Regardless, I can get one round off, maybe two if I'm lucky before I get a FTF and a fubar mag. This happens 100% of the time, even if I just load the mag up to 22 rounds and then try to unload it by hand.
I wouldn't care that much but I haven't seen anyone with the same issue so I'm a little perturbed. Something is clearly out of spec and the mag functions flawlessly without the extension. Worst case scenario I ditch the extension and try another one I guess. I'm a little surprised Arredondo hasn't tried to get back to me though...
I did forget to say that while the main reason I made that aluminum baseplate was to keep the extension from shifting I was also having the same problem with the follower that you are having. Not with your regularity but still having the problem. I still think it boils down to the locking plate. It may be too thick on the vertical side (or bent) and is 'catching' the side of the spring and taking tension off the follower making it nosedive. Thats all speculation though. How long has it been since you tried to contact Arrendondo?
-Jax
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