For those a little late to the gears of war franchise that maybe don’t want the hassle of creating a session or are just up for a challenge, this achievement is fairly manageable solo. This can be done in one sitting or multiple, just keep track of your last wave through the war journal > achievements. The initial spawn area is by far the best to do this in. Your only handicap is that there are no large ammo boxes in the entire map, just small ones. So make sure you take advantage of end of rounds to replenish ammo and pickup more Grenades. Ammo boxes are located next to each set of grenade spawns and on the top of the stairs just behind the mulched/flame thrower spawn. Rounds 7-10, 17-20 it is crucial to kill yourself some maulers and accumulate 2 boom shields. These will be used to block the 2 entrances to the spawn (doorway and the long corridor to the right). With these blocked the enemy’s will funnel to these 2 entrance points. Having a gorgon that can be picked up from the back right corner of the room behind the top of the stairs at the far end of the map will provide some extra firepower for later rounds and the ability to replenish ammo from fallen kantus. THE MOST IMPORTANT PART OF THIS GUIDE IS TO REMEMBER TO PICK UP (hold x) AND PLACE BACK DOWN (Left trigger + A) BOTH OF YOUR BOOMSHIELDS BEFORE THEY DISAPPEAR SHORTLY AFTER STARTING A NEW ROUND. These 2 shields will stop everything that funnels towards you expect for kantus, drones, cyclops, and sires. Bloodmounts, maulers, grinders, tickers and wretches will continually run into or be frozen by the 2 shields. Happy hunting