The actual gun I ran into that did not have a 4 stat card was the "Armor piercing rounds", which turns out to be a gun instead of rounds.
Not exactly. It's a modifier that allows you to make standard mass driver weapons into AP mass drivers. Basically, they'll do considerably less damage but have better range and accuracy, anda considerably lessened chance to deflect off armor (yes, gauss rounds can bounce off armor, doing almost no damage. Chance increases with the quality of the armor). Example:
Heavy Driver: 450 damage, 1050 range, 4-7deg accuracy penalty (basically, the actual shot will be 4-7 degrees off the intended line of fire)
AP Heavy Driver: 250 damage, 1350 range, 1deg accuracy penalty
The SOTS Wiki is a godsend in terms of understanding the mechanics of the game. They also have some excellent tech tree charts that show you the percentage chance for each tech to be available per race. Liir tend to get almost all the energy weapon, biowarfare and shield techs, but are kinda limited in the ballistics. Hiver get good ballistics and missiles, limited energy weapons, almost no shields. Tarkas get primarily energy, but it's fairly balanced. Humans get primarily ballistics and energy torpedos, but again fairly balanced (and usually do well in the "plasma cannon" part of the energy tree). Morrigi get primarily energy weapons, and IIRC are guaranteed beamers, which are a very nice weapon for drones. They also get some late-game gravity weapons, and almost always gets cloaking. Zuul get crap rolls on most tech beyond the basics, which provides the incentive to go out and carve up some enemies and salvage the debris in order to steal tech. They also get no biological warfare tech, but at the same time they're immune to biowarfare. And they have a pretty high chance of getting Graviton Beams if they can make it to late-game, plus a lot of "trick" weapons like Thumpers, Gravity Mines, Implosion Mines, Disruptor Whips, and Shield Breakers. I'm not particularly fond of playing the Zuul myself because they require an aggressive, expansionist player, which I'm not. But if played well, they're downright terrifying.