Latency

I know that certain guns require multiple headshots to take an enemy down. It takes even longer if the target gets to heal himself or is healed by some standby medic before you get the chance to finish the job. This makes killing with an SMG over long distance very hard if he starts out with 100% health. It is however enough if he just got hit by a snipershot leaving him with ruffly 10% of his health and no backup at that time. In other words then you get a perfect opportunity to assist in removing the tread even over longer distance. This is part of the reason the medic has the SMG's as shooting is a sidetask perhaps and he only needs to clear a path around his wounded allies. For snipers 2 shots should defensively be enough except for a few semi auto snipers perhaps. Also the hole story around TTK (Time to kill) is still under great discussion and i heard rumors about a new patch just for this behavior? but i do understand when you say only 33% of the bullets fires actually register most of the time, this is somewhat frustrating indeed!

-A ping of 1ms is extremely low unless you live as we call on top of the server? maybe for this you can do a UO Trace or look at the tcp/udp ports.