I think Robar did an experiment one time where they took a Remington bolt gun in .300 Win Mag and cut the barrel down, inch by inch, testing accuracy. Even at a bare 16", it was just as accurate (though a 16" .300 Win Mag is probably the loudest rifle you'll ever fire, short of a light fifty).
Now, 16" of barrel *might* not be enough to stablize some match ammunition. I don't know about that, but I've heard that. Still, though, for what the SOCOM was designed for I think it'll serve you well.
The biggest hindrance to accuracy reported on the SOCOM are the larger sights, which are designed for fast, close-in shooting.