Was it a Soma/CreoDron HAV? Because I'm pretty sure the Plasma Cannon hits harder against shields than armour.

So... basically a reverse Swarm Launcher.

It has definatly been brought back to useability as a anti infantry weapon, for a little bit it was practically useless in that department from whining... I hope that's not really the purpose of this thread to do again.. I only have a skinweave heavy and militia forge with dmg mod and militia cardio thing for stamina, with this I went 22 kills, 18 assists and 8 deaths the other day.. 6 of those kills were proto type heavies blasted right in the face close range as they came around corners, 2 tanks and a dropship.. it's a wonderful weapon, can't wait for the day I actually have enough skillpoints to finish assault rifles and skill up for better forge

AntiVehicle
I have been using this gun all day and I love it. You can't really use it like a forge gun. Fighting dropships is delicate work, you have to lead a lot more and make sure you are aiming for tailfins. Against tanks, I think it is meant to be used in conjunction with grenades. For example, if you used all your nades and you need one more shot. Against LAV it is really tricky. With the vehicle hp buffs and the loss of weaponry buff we cannot oneshot kill LAVS. My packed exo does a much better job. It makes a good support fire weapon against vehicles, but you just can't count on one by itself to do the job, a pair of plasma launcher gives me goosebumps.

AntiInfantry
Again, we cannot think of this like a forgegun or grenade launcher. I think of it like a shotgun. Be fast an agile, pop in fast and hop around, shoot at point blank. Make sure to hop when you shoot. This is important for 2 reasons, first is if you are in the air and the projectile denonates on the ground the splash will have less chance of hitting you while the downward vantage increase you chances of a direct hit, second if people see you jump they know you are about to shoot so they might jump too and when they do they are easier to hit because they can no longer control their movement airborne.

Definitely use peekaboo tactics. If you miss, you need to get to cover immediately or swap to smg. If it is multiple opponents, you will need to have an exit strategy planned.

Build
Caldari assault. Period. There is no other viable option. Plasma is a hybrid weapon and caldari assault give 2% to reload speed per level for a possible 25% bonus to reload speed. From 3.5 to 2.4 seconds. With plasma operation maxed we are looking at a possible 2.8 seconds per shot AFTER THE FIRST. Giving it a constant fire rate of 2.8 which is approximately 1/3 the rate of a shotgun.

If you spec into nanocirc you don't have to worry about armor or repairers, just use k17 hives. Go with kinetic catalyzers and cpu mods in low and 3 extenders and a dmg mod in high. Flaylock is a good side arm companion, flux is also nice. Thesemmakengreat splash kill combo weapons. This build is great for folks that cant aim

I honestly think CCP needs to stop putting out gimmicky weapons and start putting out a decent basic line of weapons. Both the flaylock pistol and plasma cannon are just weird weapons where, in a practical real-world sense would really not have any use at all. Why do I need a flaylock pistol when I already have a grenade? Why do I need a plasma cannon when it's bulky and only gets one shot? I'm not coming down on those who choose to use the flaylock or plasma cannon, and I'm sure people can use them quite well in some instances and have a lot of fun with them, but in the end shock troops and heavier troops need guns that mimic assault rifles, submachine guns, rocket launchers, grenade launchers and pistols in order to form an effective assault. That's honestly why I think the scrambler rifle was by far the best addition in the full release.

Now, for real ideas, if the plasma cannon was turned into something more like a mortar or artillery, that would be cool. It'd need a way to deploy it on the ground and target troops in various areas, and of course it would need a certain range put on it, but that would definitely make it a much more practical weapon, and a lot of fun too. The counter is simply, just use snipers, but a mortar or artillery weapon could make it so that those hardened targets that the other team tends to form where it's nigh impossible to take will actually have a weakness.

The splash damage should be increased

When I first played on the 14th, It was scary to see those plasma cannons fly through the air, then they found a liking to me, got hit by them at least 5 times in a few matches...

The plasma cannon projectile really likes Geth.... FML

- Geth