There is someone (Accuracy Speaks maybe?) that makes carbine-length DCM-type float tubes (i.e., the style that accepts normal handguards).  Be aware that these will add a pound or so to your rifle, and that the front sight block must be removed to install it.  They are also quite expensive at around $200 or so IIRC, being a custom part.  If you have the cash, it can be done.

But why?  Unless you are shooting benchrest-style, the extra .25 MOA accuracy you might gain will be pretty pointless, no?  And given the lower velocity from the shorter barrel, long distances aren't really practical, at least with FMJs.

The idea of a carbine (i.e., short rifle) being a fast, manueverable rifle designed for close-range work,adding so much weight in an effort to achieve a bit more accuracy runs contrary to that idea.  Just something you might want to consider, though you probably already have.

www.accuracyspeaks.com/parts.htm

Wow, I *did* remember that correctly.    And it looks like they are only $131.25.

-Troy

[Edited to add link]

Oh, and to answer your question:

Bushmaster uses the exact same barrels on their standard rifles and their V-Match rifles.  All the differences of the V-Match rifles are the visible ones:

- Float tube instead of standard handguards
- Shaved FSB (unless you request otherwise)
- Flattop upper

-Troy