Weapon Group 1: 4x HML Weapon Group 2: 4x HSL Weapon Group 3: 6x MG Step 1: Safely get right behind enemy. Step 2: Fire Weapon Groups 1 and 3 Step 3: Wait half second. Step 4: Fire Weapon Groups 2 and 3 Step 5: ??? Step 6: Profit Do not fire Weapon Groups 1 and 2 at the same time. Death or serious injury may occur.
Sadly, Piranhas don't have a place in the current division 2 of Solaris. There is no surprise moment once the opponent knows what he is up against. Tried the -1 twice now and faced an ON-IICA and a Cyclops with MRMs + LB20. No way to sneak upon them because they are aware. No chance to grind through all that armor while taking aimed counter fire.
Honest question: how about 2vs2? Either the enemy team focuses on you and potentially expose their back at bigger weapons (the one from your team mate) or risks to get dunked by +12 dmg/s with extremely high chance of critical damage... Or am I too optimist abouth the bigger team mate to either not gent dunked by focus fire or to aim prefectly on the enemy's back?
2 on 2 is the only mode I can see a PIR working well on a regular basis. This needs a very coordinated team, though, as your partner in crime won't survive the concentrated fire of two heavy / assault opponents for a long time. It might work, but I didn't had the chance to test this out, yet. The biggest problem remains: the opponents will know exactly what you and your mate will try to do as soon as they see your setup. No chance for a 'surprising' back stabbing, so why bring the PIR at all?