Gentlemen,
I have a M&P 2.0 compact 9MM and was wondering what the round count for changing out the RSA spring and the striker spring assembly. I called S&W awhile back and they had no idea. Any ideas? Also where is the best place to order them. Thanks for your time.
Jim

The flat wound ISMI recoil springs last far longer than the traditional round piano wire. I chipped a striker tip at about 20,000 rounds and replaced the entire striker assembly. I keep spare RSAs but have never worn one out or had one fail. A fellow competitor shot 63,00 rounds on one, and then changed all the springs and small parts, just because. I have had trigger springs fail more than anything else. Beware the aftermarket RSAs, which fail more than the stock ISMI ones.
I usually buy my M&P parts from Brownells, but stock varies.

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Science plus Art

1000's of rounds maybe unless it breaks , I have a 6 year old Shield still going strong . S&W will send or use to send a replacement RSA free of charge. I requested one for my Shield and bought an extra RSA for M&P FS from MidwayUSA

I have never replaced a recoil spring in any pistol I have ever owned, other than farting around with spring weights in a Colt 45 auto before I learned to leave the spring weight as originally spec'ed.

This spring I bought a used, low round count .45 Shield.
The RSA was so short it would barely stay in place, to the point of making it hard to take the slide off.
I called Smith and they sent me a new one, which has much more tension.

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U. S. Army Veteran

Gentlemen,
Thanks for the replies as all information to keep these guns up and running saves on broken parts at the wrong time. I have always kept a round count on all my semi-autos for spring replacement which can prevent cracked frames at the least. Thanks again.
Jim

The answer is "it depends" like hot defensive loads vs. weak range loads.

A "rule of thumb" suggests around 5000 rounds. I have spares for the ones I shoot more often (as well as other parts). Just keep looking and get them on sale. I have 3 for my fullsize, 2 for my compact, none for my shield (so far). I have spares for my Sig and my 1911s.

Brownell, Midway, Midwest Gun Works. S&W has sales on their site occasionally.

I haven't changed any out yet but better to "be ready" than "get ready".

Exactly what Saudade said: 5,000 rounds.
I know that Glock recommends 5,000 for it's sub compacts . I have a Glock26 ,so thats what I do. MidwayUSA sells RSA for $16.
I would imagine the shield could go a little longer because those RSA's in the Shield are very,very strong springs!

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S&W BG380, S&W 915 9mm

I picked up a spare RSA to keep in my bag at about 10K, but my 2012 Shield9 is now well over 30K rounds and still functioning great using the original RSA.

Over the last 40 Years of shooting, I've found that what manufacturers recommend and what one actually needs can be two very different animals.

There are two ways to handle springs. One is to just wait until you have a failure. This method works fine for most people. As you've seen, there are a lot of people who have fired many thousands of rounds and have no issues. So, this is not an unreasonable methodology.

A second way to handle springs is to just replace them every so often. This is a kind of cheap insurance. You can pick any type of indicator that works for you. For example, using round count is a good method. For the flat RSA in the M&P, 5,000 rounds is a good point to replace it. Or you can just use time. Every other year is a good time.

If you carry the gun for your job or for self-defense, changing the springs regularly, like every other year, is a good thing to do. You need to ensure the gun works the first time, every time.

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Freedom isn't free.

This is how I see it. When do you change your car's oil? At manufacturer-specified intervals, or when your oil light comes on and your car starts having problems driving?

I would rather spend a few dollars and replace the RSA on a regular basis (5k rounds seems like a reasonable number to me) than wait for some kind of failure to happen. It's even more important if the gun is used for self-defense, like Rastoff said.

Just my opinion.

My 48 year old Browning Hi-Power P35 (bought new) is still running on it's original springs.

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S&W Accumulator

Springs wear more from use than from sitting. So, your 48 year old [insert gun model here] might be working just fine because you look at it every now and then, but only rarely fire it. But your 2 year old gun's springs might be worn out because you have 10K rounds through it.

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Freedom isn't free.

I'm on board with the scheduled replacement plan for my carry weapon, but for my range pieces, what are the signs of an RSA weakening before it completely breaks?

I'm not really sure. For uncaptured recoil springs it's often recommended to keep a second, unused spring and compare lengths. If the current spring was noticeably shorter than the unused one, it was time to change. Of course, that's if you don't use round count intervals.

I suppose one way would be to keep an unused RSA on hand and compare how the current RSA feels when installing it in the slide/barrel group to the unused one. If the current one is noticeably easier to install, then you could change it.

You could also pay attention to ejection patterns. If you start noticing your gun throwing brass further than usual, it might be time to change the RSA.

Maybe someone else has a better idea?

Personally, I think it'd be easier to just keep track of rounds fired and replace at regular intervals. I don't think you have to be too detailed on keeping track of round counts. Just keep a record somewhere that says, "This time I shot about 300 rounds." You don't need to record, "On XX/XX/XXXX I fired 279 rounds" (I do, but I have OCD tendencies...).

I have never experienced, nor heard of a recoil spring breaking. Ever.

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

An example, for what it is worth; I have a coil spring for the throttle return spring on my 1981 Yamaha motorcycle. I can't imagine the number of times it has been fully compressed and released over the past 39 years. It is still working fine, and I do not expect it to ever break or collapse, at least for another 100 years or more.

As another example, I have several Mauser rifles that are over 100 years old. They all have coil springs as the firing pin spring and the trigger return spring. All of these rifles have the original springs as far as I know, and all of them are 100% reliable.

Yet another example, but to the contrary. I once owned a nice High Standard .22 pistol, with two magazines. One magazine worked fine, but the other had a spring which had lost its tension, and would not feed ammunition reliably.

I submit that that spring was not manufactuted properly, and that is why it failed.

What if I replaced the properly functioning magazine spring from the first magazine with a factory new, but defective spring like what was in the second magazine?

The old saying, "If it works, don't fix it" comes to mind.

I have heard about the guide rods breaking often. Plastic guides rods are more common now.
If your RSA is a captured one, Glock ,for example,then the plastic insides break and you have to replace the whole unit. Recoil springs dont break per se, .........they weaken.

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S&W BG380, S&W 915 9mm

Neither have I heard of a recoil spring breaking. I've only ever seen one recoil rod fail and that was a plastic one from a Glock during a 1,000 round torture test. The gun kept working even after the rod shot out the front.


If your gun starts to have failures to feed, it might be time to replace the recoil spring. However, a lot of people put too much emphasis on the spring. It's far more likely you'll have a failure from a broken firing pin, a broken extractor, a broken ejector or damaged feed lips in the mag, than a malfunction from a broken/worn recoil spring.

I've replaced the recoil spring in my favorite 1911 at least 5 times. This was due to regular maintenance rather than a malfunction.

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Freedom isn't free.

M&P, Glock, Sig's that will eventually get a high round count it's cheap insurance for the long run. If you will have one of these handguns for 10 years a 5k rounds it is what it is. We all hear the stories of 500k rounds in XXX and no maintenance but that is just not the norm and also not responsible ownership.

Indeed, not responsible.

We hear stories every day on the internet. Stories of 2" groups at 50 yards. Stories of 20K rounds without cleaning or maintenance of any kind. Stories of...internet bravado. In reality these stories are usually fantasy.

The truth is no one is as good as they think they are and no gun is as good as the owner claims. I'm sure some are factual, but most are "colored" a little.

I'm at the range a few times a week. I see the targets left behind and none of them at the pistol range ever have 2" groups. Especially not at any significant distance. I shoot a lot of Trap and I see guns malfunction all the time and the number one reason is dirt. Even a minimal cleaning will prevent most failures.

What is far less common is spring failure. It happens, but it's rare. Again, springs are cheap and easy to replace so, there's no reason not to. Even so, springs in modern firearms are quite good and they usually do their job.

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Freedom isn't free.

This old mechanical engineer was not a straight A student, but I paid enough attention in strengths of materials and mechanics classes to know that 99% of these recommendations to regularly replace springs are nonsense. Why do metals fail? They fail in direct tensile failure or fatigue failure. Direct tensile failure doesn't happen in firearm springs. They are constrained to a fixed deflection (strain) below their elastic limit. Fatigue failure, either high cycle or low cycle? I would hazard to say that 99.99+% of firearms springs are sized for infinite fatigue life. That means they can be cycled into the tens of millions of cycles before fatigue failure. The only remotely plausible causes of spring failure I can conjure are corrosion and abrasion, either of which is readily observable. Notice that none of the people recommending replacement cite reductions in spring rate or more exacting evaluations like microscopic evaluation of surface cracking. How often do these cautious folks tear down internal combustion engines to replace valve springs with seriously high cycle counts? How many RSA's have failed due to spring failure? There are likely some that have chewed up their guide rods and retaining collars, but fractured springs??

thanks for mentioning valve springs. they go through millions of cycles of high tension-low tension without breaking or weakening. of course they will probably fail at some point. interesting discussion.

They do occasionally fail, but more importantly if you are replacing the valves, why wouldn't you proactively replace the springs? I think the same principal applies to the RSA, it's so inexpensive, relatively speaking, when doing preventive routine maintenance why not change it?