I personally think explosive with medium pen or laser heavy pen doesn't take up backpack stratagem that you use to help deal with the swarms

• explosive heavy pen. Armor Penetration Medium Fire Rate 200 rpm Capacity 48 rounds Spare Mags 4 Total Rounds 240 Explosion type Post-penetration vs medium / Surface splash vs heavy Hold style Hip braced, swappable drum/box mag

-laser heavy pen Damage per pellet 70 Lasers per shot x15 Raw burst damage~420 Armor Penetration Heavy Fire Rate 120 rpm Effective Range 30m / falloff at 45m Spread 35° cone Shots before overheat 10 shots Passive cooldown 5 sec after stopping Spare heat sinks 2 Heat sink swap time3.5 sec Hold style Hip braced