Can I convert 10rd M&P 9 mags to 17rd?

[TheBirddog]

Found a good deal on the M&P that I want, unfortunately it comes with 10rd mags. I'm ordering some 17rd mags from 44Mag, but I want to know if I can convert the existing ones as well, or should I just sell them to some ban stater?

 

[handgunner356]

I doubt they can be converted, the compact 9 uses a shorter tube with a longer basepad. I've never seen the full size but the usually do the same or crease the sides to limit space.

 

[BigRich315]

From what I have seen of them, they are designed so they can't be modified that way. I guess it defeats the purpose if a simple spring change or similar can give a larger capacity.

You can see the difference in these pics: 10rd and then 17rd.

 

[ET.]

I would be skeptical of using mags that had been converted back to 17 round capacity even if you found a way to do it. Every time I try to increase capacity over 2 or three rounds I always end up with a mag that has one or two failures to feed in each full mag. You can buy mags for $25 each, as you probably already know, since you have some on order. I'd just use the OEM 17 round mags you've ordered and keep the 10 rounders as spares or sell them on the "for sale" threads to recoup your new mag cost. There are gun owners in states where they have to use those & will pay good money for them (as opposed to bad money?) There that was my 2 cents worth for today.

...I love it when I can assume people don't know stuff, even when they probably really do know it already. It feeds my ego that my wife has obliterated over the last 25 years by telling me "You don't know anything, God you're stupid"...