I found this on the Westwood support page and I was wondering how they calculate "K" as I was doing a little test in EXCEL and can't work it out. If people could help I would be very greatful. Math's is not my strong point. :-)

How are points calculated for C&C Red Alert 2?
Question
How are points calculated for Command & Conquer Red Alert 2?
Answer
Scoring works the same for both the individual ladder games and Battle Clan games.
The formula for determining your score amongst tens of thousands of other players is rather messy - but it works brilliantly! This scoring mechanism works in both Clan and single-player games.
RN = RO + K(W - WE)
Where :
RN is the new rating
RO is the old (pre-event) rating
K is a constant
W is the score in the event (1 = win, 0 = loss)
K is the maximum number of points you can win or lose based upon the ranks of the players involved. It can range from 1 point to 64 points.
WE is the expected score derived from the following formula :
WE = 1 / (10 ^ (DR / 400) + 1)
DR is the difference in ratings between players.
Players will never lose more than 10% of their total score during any game. All players start at 0 (zero) points and can never drop below 0 at any time.
Simply put, the higher the rank of your opponent, the higher your points per kill. The more kills or losses you cause for your opponent, the more points you receive. The more points you receive, the higher your rank. You will never lose more than 10% of your total score in any one game, and you will never earn more than 64 points in one game.