I haven't asked in about 9 months. Has there been any progress with compatible uppers or barrels in the aftermarket?

I really want a .260 Rem. I also wouldn't mind a heavier barrel for my 7.62 either.

Mike

Mark me down for a .338 Federal

Hell, what uppers (stripped or otherwise) fit the lower? Once I find out, I can assemble my own calibers.

From some trial fitting with a DPMS upper, I believe it could be made to work with some minor modifications.
The easiest and best way would be to buy a barrel extension, but it is a proprietary design that is not interchangeable with other makes. The only way to currently obtain a barrel extension would be to use one off of a complete rifle. Don't think uppers or barrels are available .

Assuming another upper will fit and function, the proprietary gas key, barrel extension, bolt, etc would not be an issue. However, I don't think there are any other uppers that fit.

Mike

What i'm curious about is whether another aftermarket complete upper (barrel + bcg + ch) will fit on the lower.

As I said in my previous post, I think a DPMS complete upper could be made to work with a little modification.
Basically the DPMS upper is wider and less streamlined than the S&W upper, and doesn't cosmetically match. It will however pin up to the lower receiver and the bolt will cycle, but the upper hits and binds on the bolt catches.
The right hand bolt catch would need to be removed on the S&W lower, then the DPMS upper would need a little bit of metal removed to allow the left hand bolt catch to operate properly. The right hand bolt catch may be able to be left on, but if i recall correctly, a lot of metal would need to be removed to make it work.
As a side note, when putting the S&W upper on the DPMS lower, the bolt seemed to protrude slightly farther out of the upper than the DPMS. This required manually depressing the buffer to get it to pivot on and pin up.
Maybe I can borrow my brother's DPMS and take some pictures of how things fit.

I think you could radius the bottom edge of the carrier a little. What worries me is proper hammer to carrier timing if the internal guts don't line up quite right. I'd hate to make some mill cuts on a DPMS upper receiver only to find out there are much bigger problems inside.

Mike

Should be getting my brothers DPMS in the next day or two to make some comparisons.
Don't think mill cutting would be necessary, it would be much easier and quicker to do it with files. To start with the bolt catches could be removed for test firing. No sense altering the upper, until it fires and functions.

Prairie, please keep us informed of your progress. The M&P is a fantastic fully ambidextrous lower and this opens up a whole new world for us.

The stock upper is almost perfect for military or police work (I'm sensing a theme here) with one lone exception*. But some of us precision shooters are looking for something different.

*-The one big fault is the clamp-on front sight. A service gun should be pinned or at least dimpled.

Mike