User blog comment:Slopijoe/What your expecting and changes in patch 1.05/@comment-1990578-20120611185900

The RPK still has ex-mags, but so do the MG36 and L86A2. They're all unlocked at 300 kills.

Oh, and the LVG fires a grenade that detonates after 3 seconds at a much lower speed than the other ammo types for the M320/GP-30. Also, kills with it count as grenade kills. Useful for trying to unlock the SCAR-L if you're horrible with grenades like me.