"Yes" but to what extent I cannot say. You'll get a bit more by accurizing the crap out of the rifle:
- You can't free-float the barrel, but like was mentioned on the other thread, you could bed the handguard.
- Get a receiver-mounted bipod or the HK heavy bipod (runs $400 *IF* you can find one - I did
- Put a good scope mount on it and a good scope.
- Use match-grade .308 ammo. (although cheap surplus .308 ammo doesn't do half bad).
- Full buttstock (there are MSG adjustable buttstocks for better cheek weld).
- You could go all-out and put a match trigger set on it like for the PSG sniper model
- Perhaps leave off the muzzle brake
- Put a target crown on it (if it does not already have one).
- Cryo-treat the barrel.
Better Range? Most likely - 6 inches extra barrel = 6 inches more time for the gases to accelerate the bullet, resulting in greater velocity and therefore greater range, and (arguably) greater accuracy.