Are any of the models of the M&P rifles piston driven as opposed to gas? I looked at all the detail pages on S&W's website but none of them mentioned a piston.

Thanks

No all gas

They are discontinued, but you may be able to find one if you really want it...

Product: ARCHIVE: Model M&P15 PSX

Here is a piston model at Impact guns
http://www.impactguns.com/smith-and-...188139396.aspx

Thanks for the info. Any reason why they may have discontinued making them?

Probably because they weren't very big sellers. Piston systems in ARs are proprietary and not interchangeable. Also, some piston designs had issues with irregular wear. I'm not sure if S&W did, as I never was interested in one. Have to wait for someone else who is more knowledgeable to come along.

Maybe slow sales? (Pure speculation.) I think the piston parts were Adams Arms so that probably added to the cost. Certainly don't see many in the wild.

So if I want a piston M&P do you think I could just throw an Adams Arms kit on a basic M&P rifle?

I don't know that specific kit but generally piston conversations were not good. Caused carrier tilt which ate away at the inside of the buffer tube. Either way buy one or the other, don't try to make one into the other.

Another thing is ...piston AR is a solution looking for a problem