Being a fan of LWRC's compact/PDW stocks and entertaining the idea for a 15-22 PDW style SBR I went ahead with my stock modification plan. Having a bunch of dental bills to deal with, the rest of it will have to wait, unfortunately. Anyway, it's an idea.

My original plan was to buy an LWRC or a CAR style stock to modify. Being forced to be frugal had me working with what I had.

The tube got shortened, threaded for a stop, and a hole drilled for what I call a storage position.
20151111_091412(0) by Slick_Rick77, on Flickr

Full in.
20151111_091323 by Slick_Rick77, on Flickr

Full out.
20151111_091310 by Slick_Rick77, on Flickr

"Storage" position.
20151111_091230 by Slick_Rick77, on Flickr

It is now effectively a four position stock with a fifth compact position. It's a little wobbly vertically fully out but fine once shouldered. A tighter fitting stock would likely work better, but I'm stickin' with what I've got. The top end of the gun is as delivered.

So far my only disappointment is that the grip screw threads came out with the screw. The hole is tight enough there's still something to grab, but if I make a habit of swapping grips I don't think it'll hold up long. As it is it's fine.

Eventually it's going to be a supressed SBR, and I'll update whenever that happens.

What parts are avaliable to buy for the M&P 15-22 that allows you to do this?

For the OP:
Being in the middle of a folder project on my 15-22 I can fully appreciate the guts it takes to cut into the one piece molded buffertube/lower reciver for the first time. Looks really good, the "stock" stock feels aged to me, this doesnt!! In a time where everyone has to have a magpul to make it stand out I really like what this did to the look of it.

15-22.

It's not butchered to me, and happens to be just what I wanted.

As mentioned the receiver/extension tube are one piece. The stock is cheap and replaceable. The receiver not so much. It can still be used with any standard stock. It's only limited to the first four positions.

Most of my guns stay unmolested. AR's of any sort get done my way.

I mocked it up yesterday with a piece of cut off barrel as it will be as a finished product.
20151120_095427 by Slick_Rick77, on Flickr

The actual 16.5" barrel is atop the rifle. The cut off 5.56 barrel stub seen near the stock was used for the mock up.
20151120_095228 (1) by Slick_Rick77, on Flickr

When I get things in order and get a stamp back it'll be a 4.5" with a 2" linear muzzle device.

The plan is to use it as a suppressor host.

It's not for everyone but I'm liking the idea. The very thought makes me giddy.

That looks Bad A**!!!

Man make me want to find another used 15-22 and do the same. Like great idea and great work.

__________________
Si vis pacem, para bellum

Now it's just convincing the wife to spend ~$900 on an inexpensive gun (trust, tax stamps, suppressor, engraving, labor for barrel cut/thread).

I figure making it useless as is may help

It'll be sitting as it is for some time. I hope to have it done by the end of next year

The idea was to have an MP5K-ish AR15-22. I think it'll work.

Now with red dot.
20151130_104925 by Slick_Rick77, on Flickr

It looks a bit quirky but aughta work.