I am trying to find info on how often the recoil spring is recommended to be replaced on M&P pistols. I have a "regular" M&P 9 (not 2.0, not Shield). Some info on the net says to replace spring every 3.5k rounds, some say every 5k rounds. I called S&W customer service, and who sounded like she wasn't even sure what I was asking said "it depends, some people need it replaced right away, and some never need replacement" (?????? ) When I pressed for their recommendations, she said she "believed" it was every 2.5k rounds.

I understand that it all depends on the type of ammo, bullet weight, +P, etc. etc. but shouldn't the manufacturer have some guidelines?
Can anyone please point me to the right direction? TIA!

Opinions vary. No hard-and-fast rules.

This was recently discussed:

round count for recoil spring assembly replacement?

Personally, I think 5k rounds is a good number for replacing the RSA as a part of routine maintenance.

Thanks for a prompt response!

I would HOPE it is in the owner's manual. I have not looked at the manual for my Shield in a while, so it may not be in there ...

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NHI, 10-8.

For a 5" 1911, manufacturers often say
How often should the recoil spring be changed? The recoil spring should be changed, at the latest, when it has lost 0.500” of free length from new. At this point, the spring has suffered a considerable reduction in load exerted at installed (when the gun is in battery).

For the flat wound springs like the full size M&P, this method does not work, and fatigue testing on the flat wound springs gives incredible results:
How long will an ISMI recoil spring last? In independent testing, ISMI spring have endured in excess of 100,000 compression cycles. We don’t recommend going that long between changes however. With an ISMI spring, practice routine maintenance and change it once a year.

Once a a year is reasonable for competitors, who may shoot many tens of thousands of rounds a year. ISMI guarantees their spring for one year, regardless of the number of rounds fired. I personally have fired over 20K in one year, and a friend fired 63K. Both recoil springs were still fine.
For the average shooter who shoots a few hundred shots a year, a RSA may last a lifetime.

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Science plus Art

The manual doesn't "suggest" a replacement interval. Since the spring(s) are captured, it's hard to measure free length.

I have also heard the 5,000 round interval yet some folks on here have gone far beyond that.

Recoil spring assemblies are fairly inexpensive ($15 for full size) so I have a few spares for my fullsize, Compact and Shield. I'm nowhere near the round count on any of them and will change them out when I start to have issues. However, mine are range guns (so far) so I can "afford" to wait until it fails.

It's not in there. In fact, the manual makes no mention of replacing this spring at all.

As has been seen in the other thread, I don't know of any recoil spring that has failed or worn to the point where it causes malfunctions in an M&P. Sure, people replace them just because, but there really isn't a hard round count for that.

Replacing parts like this is cheap insurance so, replace them every 5K rounds and you can't go wrong. You just don't have to.

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Freedom isn't free.

Smith & Wesson do have service intervals for the M&P where changing certain components is part of the service. The service schedule is a must for service pistols that are issued to LE and MIL, but only a recommendation for civilian use. S&W recommends replacing the recoil spring assembly for every 5000 rounds fired.

But do you really need to replace it at every 5000 rounds? No. Will you ever have the need to replace it? Probably, one day, perhaps.

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Hello darknes my old friend

In mid/late June, 2018 a retired armorer, screen name Fastbolt, listed the suggested replacement intervals on the M&P series. A search ought to turn that up.

FWIW, recoil spring assemblies "should" be changed at 5K rounds/5 years. I went beyond the 5 years, doubt I did 5K rounds, but when I changed, I could notice a difference in the effort needed to rack the slide. Wasn't much difference, but noticeable. Spring assemblies are much cheaper than a frame. Some years back, a member mentioned that it cost him $199 to replace a frame his pooch gnawed on.

I found this thread from 2015. Rather than post the link (resulting in the inevitable necroposts), here's the gist of it:

Thanks to member Deadbug!!

"The other day I contacted S&W customer service to ask about a preventative maintenance parts replacement schedule for the M&P Shield.

The only guidance/recommendations they provide is for the Law Enforcement Community--and that is listed below. Thought it might be of interest to all who use their Shields for EDC:


M&P SHIELD MAINTENANCE SCHEDULE (Law Enforcement)

1 Year/5,000 Rounds:
Replace RSA
Mags: Replace followers and springs

10,000 Rounds:
Replace Trigger Return Spring
Replace Trigger Bar Assembly
Replace Striker Assembly
Replace Frame Coil Pins"

The post specifies the Shield (1.0), but I'll guess it applies to the FS and Compact. Although all 1.0s at the time of his post, I also guess it's applicable to the 2.0s.