Depends on the type of game you are making.
So without knowing that it is hard to tell what the best option is.
In my wip top down shooter i spawn a sprite "line" on each shot.
1 on the pc of the player that is shooting.
And on on all the other players pc's.
The shooting player spawns a "dummy" and raises a photon event to the other players with the data which players is hit and by who and the type of gun.
The other players receive that message, and this time the "real" sprite line is being spawned hitting the player, and if the name in the photon event data matches their own player, then uppon this event, life is substracted according to the gun that whas used.
Then this player being hit raises a photon event with its own life information and player name to the other players updating life status.
Note that this method does not involve flying projectiles.
Its a instant hit method just like raycasting in 3D fps shooters.