I was discovered quite accidently while modding a BAR for a friend who wanted a scope on it that I can eliminate the recoil of the gun. The server's settings still control bullet SPREAD, and wont allow the scope or firing rate modifications, but I was able to keep a no-kickback BAR regardless of what any other the servers i tested this on dictated. (tested on about 8 of the bigger more popular servers)
I also added to the mod smokeless gunpowder and a flash supressor.
When you dump a clip your crosshair stays perfectly on target. While bullet spread is still server-side, eliminating recoil is half the battle of staying on target and it works like a charm.
For skeptics....
http://members.shaw.ca/ctrl.alt.del/bar_cheat.wmv (30 seconds) Note the lack of flash, smoke and a perfectly still crosshair when I kill the sniper on automatic fire... (you see his smoke... whether or not others see mine i do not know.)
Can you have it? No.
Why post this? Because some people swear no cheats exist other than glitches.