when comparing a range pure to a range tank of the same combat level, generally the tank will have less ranged level than the pure because of the tank's defense level.
But the tank can generally outlast a pure of the same level as he is (even some higher levels) if the defense and range of the tank are high enough.
For range pure, it's better to leave defense, prayer low. Get your range above 70, maybe 60 strength and 40 attack for a 2h ko in f2p.