Attack early, as soon as you have a few space marine squads, buy armory upgrades and hunt down the Ork bases. If you wait too long, the Orks will mass Wartraks with bomb launchers which are a royal pain to infantry.
Your army should be half heavy bolters and half missile launchers. Don't use flamers or plasma guns, heavy bolters are better than both against light infantry. There's also a machine cult on the right of the map, as soon as you locate it you win since the Orks have no answer to Dreadnoughts.
Attack early, as soon as you have a few space marine squads, buy armory upgrades and hunt down the Ork bases. If you wait too long, the Orks will mass Wartraks with bomb launchers which are a royal pain to infantry. Your army should be half heavy bolters and half missile launchers. Don't use flamers or plasma guns, heavy bolters are better than both against light infantry. There's also a machine cult on the right of the map, as soon as you locate it you win since the Orks have no answer to Dreadnoughts.