The AR15.com Ammo-Oracle:
M855: Defined in MIL-C-63989
NATO specifications for M855 Ball require a 61.7 grain (q 1.5 grains) with a hardened steel penetrator at a velocity of 3,000 fps (q 40 fps) from a 20" barrel @ 78 feet from the muzzle. Typical velocity 15 feet from the M16A2's muzzle is 3,100 fps
Its ballistic coefficient is typically 304.
Both M855 and M193 in the US generally use Olin Ball WC844 propellant. Apparently H335 is roughly equivalent to WC844.