My sugguestion is a new kind of ammo:
Nitrogen bullets
Requirements: Alien Materials
Description:
The research, to fill bullets up with liquid nitrogen, is about 30 years old. Aim was to research a flechette ammunition releasing a decent amount of liquid nitrogen over heavy armor on impact that would brittle the material and makes it useless for protection.
The only progress we made was in anti tank ammunition. The grenade consists of two different parts. The back of the grenade is just a dewar flask filled with liquid nitrogen, while the front is prepared with a contact explosive strong enough to crack up the mantle of the projectile on impact.
However, this technology was not adaptable on bullets. Bullets are too small a dewar flask would be a possibility to storage the liquid nitrogen without vaporization. The ammount of nitrogen is much smaller in a bullet than in a grenade. Both problems require to store the liquid nitrogen in the bullet with high pressure.
This leaded to the problem to research a bullet body strong enough to endure the pressure of the inserted liquid nitrogen, but still being cracked up on impact. To work with an explosive head, like we did on the greandes, was no option, because even under high pressure the ammount of nitrogen stored in one bullet is not very high, so the kinetic energy caused by an explosion would conter the freezing effect of the nitrogen.
The solution to this problem is in the alien Materials, since it is strong enough to widstand a high ammount of pressure even if the material is only some nanometers thick and changing its form depenent on heat. So we were able to produce a bullet that has predetermined breaking points consisting on alien materials only some nanometers thick. The material is thin enough the friction energy of an impact is enough to make the bullet change its form and to crack up on impact. The freezing effect of the nitrogen loweres the integrity of the amour and leads to frostbites.
However the production of this ammunition is still very expensive. But this ammunition has some more drawbacks. If fired on unamored enemies the friction energy on the impact may not be enough to cause the bullet to crack up. The damage done may be lesser than the damage of a normal bullet against unamored enemies.
Since the core of the bullet is liquid the flight characteristics of this bullet is slightly different. Aiming is a little bit harder with this bullets and the range is reduced. The magazine is very reactive to heat. So if you carry arround a magazine of nitrogen bullets take care not to be set on fire or be target to explosions, since the heat may be enough to cause the bullets to crack up.
Effect:
The damage of the bullets is reduced. The accuracy and the range is reduced as well. But hitting with a nitrogen shot reduces the amor value of the hitted amor part permanetly.
Greetings
Prinegon.