Make the players strongest possible but one head shot, with full shield kills them, and make their shields recharge 200%. It makes headshots the most efficient way of killing someone, unless there's something just as powerful as that headshot; so no rockets, splazers, ect. Team swat is an example of this. I've done this with many maps including dodgeball and it works good, this is the best technique your gonna get. Why do you want to know this btw, you making a snipers game?
can some one like send me the swat game type or pics of what to change settings or send me FR and show me
All you need to do is put the damage resistance of everyone to 2000% and make it so everyone has no shields and Snipers.
there's no true way to completely make players invulnerable except for headshots. Although what has been mentioned about damage resistance and shields will capture the effect you are going for as close as possible