Sorry Richard, I am a long-time member of the CDTSA, but I don't compete in the Service Rifle Matches. I may give it a try next year, though!
For a brief overview of the CDTSA Service Rifle Match Rules, go to this link and scroll down the page a bit;
http://cdtsa.org/files/2009%20Event%20Schedule.pdf
Of course, in order to participate in the matches, one has to be a member (in good standing) of the CDTSA.
Hope this helps,
GW