You mean hijack an Atlas? I got that one on my first playthrough, on the Atlas that appears on the Citadel. You need to kill the pilot and take that same Atlas without destroying it, and it's not as easy as it seems, since pretty much only Snipers can break through the glass and the most powerful ones will destroy the Atlas before you can even shatter the cockpit. 

How did you manage 200% with those three weapons on Insanity?

Soldiers kinda suck this game.

I really don't think so. My first playthrough was with a Soldier on Hardcore difficulty and I managed quite easily. Adrenaline Rush is your friend

Sorry, I was unclear. I meant Soldiers suck compared to the other classes. The single-player is easy enough that romping through on Insanity is not really a problem, but it's much harder to do as a Soldier than it was as an Adept, Sentinel, or Engineer (the other classes I tried). Perhaps it's just my playstyle, but considering I preferred Soldiers in ME2, I don't think that's it.

Oh on that I do agree. Every other class is preferable to the Soldier one, even if just for a more varied gameplay and strategical approaches to confrontations, since with the Soldier one you're just pretty much limited to switching between what kind of ammo is more appropiate for every situation.

If something needs to change in the MP is the frigging quitting mechanic. Install some sort of penalty, like losing credits or something similar, but they need to do it pronto.

I've had it enough with people leaving mid matches in Silver and Gold. As an Infiltrator I can survive for a while, but it gets damn near impossible with other classes and I'm usually left losing some bonuses I used for that round. Frigging idiotic.

Oh lol I fail. I thought hijack meant sabatoge a Atlas. I didn't know they meant kill the driver and steal his Atlas.

I got 200% because as an Infiltrator I can make some weapons weigh less. Plus I had them all up to the highest level so they weighed much less...also I had the mod on the tempest that made it weigh 80% less. I could have had slightly heavier weapons and still have 200% recharge.

Yeah, I only found out because I screwed up on my load for that mission and instead of the N7 Valiant, I put the Incisor rifle and was able to kill the driver inside XD. The Valiant would have destroyed the Atlas's armour in 3 shoots with the AP bullets even on Hardcore.

Well, the Phalanx and the Tempest really do weigh next to nothing, especially on X and the Viper is one of the lightest Snipers in the game as well, so I can see those 200% with the proper build. Probably going to try it myself, but I just love my current load of Black Widow and Phalanx XD.

I used to have a similar setup in the first runthrough of the game but I just couldn't stand the longer power recharge speeds.

I actually used to have the Mantis/Phalanx/Tempest combo (still +200% recharge speed) but I ended up going with the Viper simply because it did 80% of the damage the Mantis did but shot twice as fast. Even on Insanity I could take out anything besides Phantoms, Atlases, Banshees, Brutes, Geth Primes and Pyros with one shot after I quickly disintegrated their shields with Energy Drain. And I put the Piercing mod on the Phalanx so I could get rid of shield guys and Brutes faster.

I guess I'll have to use the Incisor Rifle to get that achievement quick since anything else will probably be too strong.

My MP Viper is almost to X as well and when it hits that i'm going to switch the Mantis for it, though I wouldn't mind getting a Black Widow one of these days .

Even with all the BW's weight, it's still an amazing SR with the same piercing capacity of the normal Widow. At X, the BW should weight similar to the Mantis X no?