I think there was someone working on this not too long ago, so maybe they'd be willing to help you out? Try searching back a page or two and you should find the thread.
Yes, I have already implemented this, at least the same way day of defeat does recoil (the crosshair moves upward when shooting).
You basically need to use Client.SetPitch() and Client.SetYaw() to modify the viewangles when you fire a bullet. Here is the thread where I was asking about it: <a href="http://www.unknownworlds.com/ns2/forums/index.php?showtopic=122026&st=0" target="_blank">http://www.unknownworlds.com/ns2/forums/in...122026&st=0</a> (note: there was a bug at the time causing weird behaviour, but it's been fixed now)
I can post the full code up if you want but it's a little messy at the moment as I just quickly implemented it.
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You basically need to use Client.SetPitch() and Client.SetYaw() to modify the viewangles when you fire a bullet. Here is the thread where I was asking about it: <a href="http://www.unknownworlds.com/ns2/forums/index.php?showtopic=122026&st=0" target="_blank">http://www.unknownworlds.com/ns2/forums/in...122026&st=0</a> (note: there was a bug at the time causing weird behaviour, but it's been fixed now)
I can post the full code up if you want but it's a little messy at the moment as I just quickly implemented it.