get yourself a K98 that was modfied by the Israelis. It will be a 308 instead of 7.92x57 (8mm Mauser)
Not really easy to find ammo for, plus all the ammo in US is downloaded, so it will be worse than a 308.
For the beginning, get a 303. As for the brush busting.... I doubt there's anything labeled as a brush gun.... A 45-70 woud be the closest you can get . After that, there's minimi gun, but things get rather expensive at that point for brushbusters.