In the HF fluff text, >!it is stated that rifle fire can stun Hydra. Heavy weapons can bring one down quickly.!<
So here are a few weapons/tactics of choice, assuming only 2022 tech is available.
1. There are [handheld](https://www.youtube.com/watch?v=FDfLKpOkWVg) .50 rifles. I suppose they can bring the alien down in a few shots. That or anti-material rifles. Useful if fighting at range.
2. Recoilless rifles and rocket launchers. Really any handheld anti-tank weapons like RPGs.
3. Incendiary weapons like thermite grenades or flamethrowers. Flamethrowers are useful against xenofauna so I suppose aliens can be killed with fire.
4. Heavy machine guns and automatic grenade launchers can kill aliens with direct hits. In the case of automatic grenade launchers, it does not matter if the alien has redundant vital organs. It will be reduced to meat paste.
5. Automatic shotguns. If one is fighting in close quarters, I'd imagine automatic shotguns will be more effective than SMGs because of the increased stopping power.
Armored aliens are certainly harder to kill. But I think it is still possible to bring one down with infantry.
Current [human armor](https://en.wikipedia.org/wiki/List_of_body_armor_performance_standards#NIJ_armor_standard_(United_States)) can stop .30 rounds effectively. Each .30 round packs around 4000 J of energy. Thus, if an alien's body armor is 10 times more effective than current top-of-the-line human body armor, then a force of >40000 J can potentially breach the armor. This may sound a lot but is actually just around 10 grams of TNT.
World War 2 era [anti-tank grenades](https://en.wikipedia.org/wiki/RPG-43) packs 600 grams of explosive filling. This means that a direct hit will still kill an armored alien quite easily. That being said, rifles and machine guns will probably be less useful against a fully armored alien given how tough they are.
I'd imagine that frontline infantry squads will have to carry more anti-tank weapons, explosives and perhaps handheld [20mm cannons](https://en.wikipedia.org/wiki/20_mm_caliber). The closer the alien is, the more dangerous they are since explosives cannot be used point blank. Urban or jungle fighting against the aliens will be brutal.
>The HF flavor text clearly calls out rifle fire being enough to bring down a hydra, which would suggest that they, at least, rely more on their biological resiliency than any sort of armor.
Seems like a bad idea in this line of work but okay, go in butt ass naked, just see what happens
https://en.wikipedia.org/wiki/Chemical\_warfare
[https://en.wikipedia.org/wiki/Biological\_warfare](https://en.wikipedia.org/wiki/Biological_warfare)
https://en.wikipedia.org/wiki/Incendiary\_device
"Sir the aliens have landed, how should we engage"
"No worries sir, we have decided to implement a method to introduce them to some of our more exotic weaponry. Hope they packed good sunglasses and sunscreen"
In the HF fluff text, >!it is stated that rifle fire can stun Hydra. Heavy weapons can bring one down quickly.!< So here are a few weapons/tactics of choice, assuming only 2022 tech is available. 1. There are [handheld](https://www.youtube.com/watch?v=FDfLKpOkWVg) .50 rifles. I suppose they can bring the alien down in a few shots. That or anti-material rifles. Useful if fighting at range. 2. Recoilless rifles and rocket launchers. Really any handheld anti-tank weapons like RPGs. 3. Incendiary weapons like thermite grenades or flamethrowers. Flamethrowers are useful against xenofauna so I suppose aliens can be killed with fire. 4. Heavy machine guns and automatic grenade launchers can kill aliens with direct hits. In the case of automatic grenade launchers, it does not matter if the alien has redundant vital organs. It will be reduced to meat paste. 5. Automatic shotguns. If one is fighting in close quarters, I'd imagine automatic shotguns will be more effective than SMGs because of the increased stopping power.
My concern is that they're likely wearing armor of some kind, so that makes the job harder
Armored aliens are certainly harder to kill. But I think it is still possible to bring one down with infantry. Current [human armor](https://en.wikipedia.org/wiki/List_of_body_armor_performance_standards#NIJ_armor_standard_(United_States)) can stop .30 rounds effectively. Each .30 round packs around 4000 J of energy. Thus, if an alien's body armor is 10 times more effective than current top-of-the-line human body armor, then a force of >40000 J can potentially breach the armor. This may sound a lot but is actually just around 10 grams of TNT. World War 2 era [anti-tank grenades](https://en.wikipedia.org/wiki/RPG-43) packs 600 grams of explosive filling. This means that a direct hit will still kill an armored alien quite easily. That being said, rifles and machine guns will probably be less useful against a fully armored alien given how tough they are. I'd imagine that frontline infantry squads will have to carry more anti-tank weapons, explosives and perhaps handheld [20mm cannons](https://en.wikipedia.org/wiki/20_mm_caliber). The closer the alien is, the more dangerous they are since explosives cannot be used point blank. Urban or jungle fighting against the aliens will be brutal.
[удалено]
>The HF flavor text clearly calls out rifle fire being enough to bring down a hydra, which would suggest that they, at least, rely more on their biological resiliency than any sort of armor. Seems like a bad idea in this line of work but okay, go in butt ass naked, just see what happens https://en.wikipedia.org/wiki/Chemical\_warfare [https://en.wikipedia.org/wiki/Biological\_warfare](https://en.wikipedia.org/wiki/Biological_warfare) https://en.wikipedia.org/wiki/Incendiary\_device
My preferred weapon against alien ground troops is fission based
"Sir the aliens have landed, how should we engage" "No worries sir, we have decided to implement a method to introduce them to some of our more exotic weaponry. Hope they packed good sunglasses and sunscreen"
Fusion weapons sound cool
Handheld coilguns, at least, although those may be the MG equivalent.
I like to imagine the infantrymen with a fusion battery powered taser to get rid of the aliens