Aliens are invading earth! Pouring from portals hidden deep in the earth for millennia, they are sweeping aside the militaries of earth with contempt. Modern infantry rifles, even loaded with armor piercing ammunition cannot penetrate their fully body armor suits. So far, the only small arm to damage an alien soldier has been a large-caliber anti-materiel rifle. Tank rounds and heavy artillery are effective, but without infantry support they are easily overrun and destroyed.
Alien soldiers are equipped with conventional firearms that are unable to penetrate their own armor. (This is believed to be a chillingly pragmatic choice to prevent us from copying their technology.) These weapons are roughly equivalent to a M60 LMG and are used as assault rifles by the physically stronger alien infantry. They do, however, deploy a highly effective anti-armor missile system.
The alien portals are scattered across all of earth's continents, and no one is sure that all of them have been identified. Several of them are sited underneath major population centers. Alien force strengths are difficult to estimate, but human forces outnumber them by 3 to 1 on average. Alien troops receive supply through their portals, but have been quartering troops in human structures.
Alien armor is, from the few samples recovered, an advanced ceramic plating. Ballistics tests and field reports put it on par with the armor on a modern military armored car, but much lighter and more mobile.
The question is this: What can humanity equip its infantry soldiers with to counter this enemy?
- Access to all the military technology of today's earth
- The weapon should be either already broadly available or easily mass-produced. The forces of earth need access to it yesterday.