OK, so some basic things about synergies:
You can't simply add synergy mods to a gun and expect to reap the benefits. The gun that you are modding out must have that synergy already on it. For example, you have a VOT Grind Fragger with Brutal on it. In order to reap the benefits of the Brutal bonuses you must attach mods to it that also have the Brutal Synergy. For every additional Brutal synergized mod that you attach you'll gain the corresponding bonuses. Thats what the [1], [2], [3], and [4] mean. Other synergies such as Grenedier, Quartermaster, and Assassin are the same way.
Now there's another type of synergy that you should be aware of. That one is preceeded by a [2] instead of 1-4. What that means is that you need two weapons of that synergy equipped in the same loadout. For example, I have a VOT Outbreaker and a VOT Mass Cannon with Veteran. Veteran applies a 10% RoF bonus for 2 seconds after a full reload
if I have two weapons with Veteran equipped in the same loadout. Since both of those weapons I mentioned have Veteran then I get that bonus every time I reload from an emtpy clip. The Veteran, Survivalist, Wrecker, and Outlaw synergies are like this.
There we go. I hope that cleared things up a little for you there OP.
