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MP9 Pro 5'' recoil spring question


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Does anyone know the approximate round count lifetime of the stock recoil spring on MP9 Pro 5''?

What signs would I notice when the recoil spring is near the end of its lifetime? I'v heard early unlocking (causing accuracy degradation) when the recoil spring is becoming too soft. What else?

Also Speed Shooter Specialties carries 2 models of non-captured guide rods for MP9.

One says Fits M&P 4.25" & 5"


The other says M&P 5" only


Anyone knows the difference between these two? I wonder if both would work on the Pro 5''



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When I was experimenting with how light I could go with recoil springs the tell was when it got dirty, about 100 rounds, it would intermittently start not going back into battery. Since I got one that works I haven't had a problem in over 10,000 rounds, same spring.

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I have read 7000 rounds on the stock M&P spring. For me, feeding issues are usually the first sign that something is up and time to change the recoil spring.

For the non-captured guide rods, the first one listed is shorter and will fit flush with the front of a 4.25" gun and will be recessed about 3/4" from the front of a 5" gun. (like a stock guide rod) The second guide rod is longer and will stick out about 3/4" from the front of a 4.25" gun but will be flush with the front of a 5" gun. It adds a little bit of forward weight over the shorter guide rod.

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  • 1 month later...

I just keep a rule of thumb to change all gun and mag springs every year. I would save the money and buy the oem recoil assembly. Take the hex screw out of the end and drop in any ismi flat spring. The factory guide rod is stainless also. This way you can change your spring to a different weight with a drop in assembly. This works really well for shooting different weight bullets and loads.

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