"thrown further" = "arremesada(s) mais longe/a uma distância maior"
The distinction between the words farther and further has about disappeared. If you do not know which to use, opt for further. (Non)native speakers of English all over the world have slowly begun to use/adopt (or shown signs of using/adopting) further a lot more than farther.
Thus an English-speaking grenade thrower may throw his granades "further", rather than "farther".