Are any of these servers what you are looking for?

Servers with "Crossfire" and "AR51" in the name:
[AR51] CRK 24/7 Crossfire #1 By WWW.AR51.EU
[AR51] CRK 24/7 Crossfire #2 By WWW.AR51.EU

Servers on :
[AR51] CRK 24/7 Crossfire #2 By WWW.AR51.EU
[AR51] CRK 24/7 Crossfire #1 By WWW.AR51.EU
[AR51] Sniper Only FastXP Only #1 By WWW.AR51.EU