these RAMs use either
0.43 or 0.40 [the former is the usual standard calibre used
iirc]
i cannot recall if they have an adjustable hop-unit - if it does
then it can fly pretty straight for a longer range than you'd
otherwise think, coupled with an increased velocity [also
adjustable - but 400fps was a quoted shipping velocity last time i
checked].
because of their calibre they are not permitted in normal paintball
games or tourneys.
they are not 6mm - 6mm paintballs are the same calibre as airsoft
guns, but are not recommended as they are known for breaking within
the mechanism and wrecking the inside of airsoft guns.
Yup,the paint used in paintballs are all bio-degradable.Even a
slight drizzle can wash them off
the paint is water based.