Just took a new M&P 9 pro to the range tonight to break it in and had some issues so I'm looking for some suggestions. Just for the record this replaces my M&P 9 I used for a couple years in IDPA comp w/o ever a single malfunction. During the course of about 200 rounds I had at least 6 stovepipes and for the majority of the mag loads the slide failed to lock back after the last round. American Eagle, UMC and PMC factory ammo was used and the gun was cleaned and well lubed with break-free.

I'm suspecting an overly heavy spring but a guy at the range pointed out there are 3 different followers on my 6 S&W factory mags. The two that came with the Pro have higher followers (although I'm almost certain I got a slide lock failure with the new mags), two came with my M&P 9 fullsize and I bought two off the shelf. One has a black follower and the rest are gray.

So I'm wondering if I should go with a lighter spring for typical factory loads, replace my old followers or both. Or maybe theres another issue???

Jim

I'd say you should confirm whether or not it's a mag problem. That seems to be the fastest/cheapest thing to get out of the way initially.

I just bought an M&P9Pro a few weeks back. About 350 rounds through it without an issue.

I think that you may be having some malfunctions from being early on in the break-in process. Keep track of your magazines and get at least several hundred rounds through your gun before being concerned. All the malfunctions with my M&P9 and M&P40 occurred early on, nothing since. Also I have the impression that the M&Ps like ammo with some umph.

__________________
I shoot, therefore I am.

If possible, nail down what mag is in her, and what follower is in the magazine's tube when you experience, whatever you experience. Having that many wild weasel's (no USAF pun intended!) running around makes it a nearly impossible number of permutations otherwise.

Mine only likes 115 gr 9mm ammo. I was givin some 124 and it did not like
it. Good luck

I have a nephew shoots reload 124gn. much lighter on power than the factory ammo load, it cycles just fine. I don't think this has anything to do with ammo!

Thanks folks... I contacted S&W and got a one line response to send it back for service. I think I will run a couple 100 more rounds and see what happens first. I've also been looking around and the consensus seems to be a lighter 18 pound spring works better than the stock 20. Also tried to find replacement followers for my old mags w/ much luck. Guess I'll have to call S&W on that one...

The conclusion is the gun has a spring that is either too tight or not adequately broken in. I went to the range a few days ago and replaced the guide rod/spring with the well used one out of my M&P 9 fullsize. Several hundred rounds using all three mag variations and I could not get a single malfunction.

Glock-no break in, no problems.

S&W revolvers-no problems.

S&W autos-...

Don't paint all SW autos with the same brush.
Sigmas very very rarely have any break in problems at all.
I have had more issues with Glocks than new Sigmas.
3rd generations rarely have any issues at all either.
MP and 99's are entirely different guns.

Where in the world did you get the idea that the recoil spring in the M&P is 20 lb?????????????? The factory spring rating for the regular M&P (non .45) is 16 lbs. I expect it's the same spring in the Pro.

The original M&P 9 followers were black, the gray ones have a slightly higher profile to ensure slide lock back. I've experienced no issues with either follower in thousands of rounds.

Minor issues like those you experienced aren't unusual in brand-new pistols.

There have been revisions to the M&P followers? Could you post pics of the differences?

This is a most unfair and overly broad generalization. Having used all three mentioned, I can say that GENERALLY Glocks, S&W revolvers and S&W autos ALL work from the first trip to the range.

On the other hand, in the 40+ years that I have been shooting, I have experienced problems with all three categories you mention on the first trip to the range.

Examples of failures (all brand new at time):

G17: Slide repeatedly failed to lock back and had to go back to have notch re-cut.

S&W M27: Cylinder locked up "tighter than "old Dick's hatband" on first firing. Tiny sliver of lead fell out of action when side plate removed and parts taken out. Inspected and reassembled. No other problems - ever.

S&W Autos: M4506 would not feed hard ball ammo. Comparison with mags from previous 4506 revealed the front wall of the mag was significantly higher and actually interfered with feeding of cartridge. S&W replaced all of the newer mags and changed the mag design again.

Thus, I do not trust anything UNTIL it has proven itself to be reliable. Anything can fail. Glocks are not immune. Feel free to check other sources for Glock issues such as re-design of firing mechanism and safety called an "upgrade" instead of a recall, or the several thousand pistols that had to have frames replaced because the molded in rails were out of spec (either set in too high or too low), causing the slide to run amock and shear off rails, and other issues.

That said, ALL of the guns mentioned are EXCELLENT. It is merely proof that anything made by man (or woman) can fail.

I don't know about the 9mm followers, but I know there have been revisions to the .40 & .45 followers.

Sorry, I don't have pics at this time.

I do, however, have 3 different .40 followers out on my bench. The last one is a very recent change.

I ordered some spare .45 followers and the shipping notice refers to them as "REV", meaning they're a revision (no letter or number code for the revision, though).

This isn't unusual, however, as many of the M&P pistol parts have been revised since the model line was released in Jan '06.

Also, S&W is constantly revising parts, even of existing model lines, as a normal course of events. Sometimes the revision may be because of a change in vendor, a change in how a vendor makes a part, a change in spec, a change in manufacturing process, etc.

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Ret LE Firearms inst & armorer

I posted the ... for exactly the reasons that you posted above. I would gladly venture into hostile territory with a 3rd gen auto, and a Sigma may as well be a Glock. However, if someone said, we'll be giving you a S&W auto, and I didn't know that it would be a 3rd gen for sure, I'd be much more nervous about my equipment. I don't consider Glocks the be all and end all for all auto's, but the 9mm models tend to come close for me, just the same a S&W revolver does for me as far as a revolver in any caliber.

mp pro. the first gun i have ever owned. my friends took me to the shooting range. nervous at first. my buddies enjoyed shooting the gun more than me i believe. no issues whatsoever. yes i shot there guns too but believe i made a good choice. very happy with it.

oops i bought the 9mm and just picked it up a week ago