42 1 2It seems like you need to get the killing blows with the Grizzly's cannon and not machine guns. Also make sure that exploding barrels/passenger marines don't get the killing blows!Showing both comments. Leave a comment. I think you're right. The first time I tried, I didn't get it and I think I might have destroyed one with the machine gun turret instead of the cannon. The second time I tried, I made sure to use only the cannon on them and I got it.Posted by olanmills on 24 Sep 13 at 08:34 Yeah I can confirm it's cannons only. If you shoot them at all with the machine gun it will void the achievement.Posted by Fooga on 06 Jan 14 at 15:25 Leave a comment