I quite frankly have no trouble killing the same level pures (str pures, range pures, mage pures etc) because I'm able to out-last them in fights as well as do significant damage due to their poor defense.
For str pures and mage pures, I find them quite easy to kill with just ranged. Str pures might hit you high, but they often have trouble making hits, you just mow them down with increments of smaller damage (but still significant).
Range pures are the same. Even though a range pure might have 60 ranged compared to a tank with 50 ranged, in f2p, damage dealt with ranged aren't that significantly different. He might have 60 ranged, and hit 9 with an iron arrows while you have 50 and have no trouble hitting 7's on him. Plus, your defence will outlast him too.
Just becareful of other tanks you face.
I personally have no trouble taking down level 61 full-runers BECAUSE I've made my tank into a range/mage tank. If they have full armor, i'll just range/mage combo them until they're dead.