A heavy 100m away spamming away with an orion will beat even the most skilled infiltrator just because of the combination of these mechanics. Considering most infantry won't render much further than that this is pretty much "long" range. A heavy generally takes 5 hits to kill with the semi-auto which is usually not difficult unless they're shooting at you even at long range the most glancing hit makes your aim bounce around like a drunk sailor. Don't even think about trying to get a headshot. It is not fun and really limits the class.