The environment question still stands.
Does nobody here remember how the sport rifle used to work? It had projectiles that did exactly this, it ignored collision with everything except for players. I recall it being taglined as 'super piercing bullets'.
mask is not a thing for projectiles.collideWithPlayers = false; //assuming you don't want other players to be able to intercept them.isBallistic = false; //this is default anywaysarmingDelay = a number in ms that should be equal to or higher to how long you plan on having it travel;then just schedule it to explode when it would come close to the player. or whatever.