Question regarding M&P15T buffer/spring for Magpul UBR upgrade

AR/M4 AR General Discussion
1

I have a M&P15T and wanted to change the stock on it with the Magpul UBR (http://store.magpul.com/product/30/86) and it recommends an M4 buffer and spring for it since it doesn’t come with them. Could I use the same one that came with the rifle?

On a related note, are all M&P15’s milspec?

2

The UBR uses an entry length tube which is compatible with carbine buffers and springs. Its basically an A2 tube shortened to carbine length.

Milspec in what way?

3

the receiver for the stock

4

So I can use the stock buffer & spring then?

5

Yes, and they are mil spec rec ext’s…