MechWarrior 5: Clans

The Timberwolf's TBR-D OmniPod set gives you access to four separate missile hardpoints, two on each torso. It comes stock with Streak SRM6s but you can also swap them all out for SRM6s with Artemis IV, which kicks the damage up a bit and improves the spread while also removing the lock-on requirement. It'll take a few missions but if you get close to an enemy you can dump salvos of 24 missiles into them over and over until they're a smoking pile on the ground and/or the achievement pops.

You can also use regular SRM6s instead to cut down on weight and bring more ammo. Same damage, but they hit a slightly wider area.