Will there be weapons on Mars colonies?

What weapons would likely be used in a war on Mars?

In the projectile weapons arena, there are many options that don't risk breaking into a wall but have enough stopping power to incapacitate a soldier. These are generally lesser force and range laps than a normal lap, but the range should be very limited in a small Martian habitat.

For example, the Glaser Safety Slug is a pistol or a bullet that disintegrates into a bird's shot at very high speed. It penetrates clothing and meat, but not much thicker material than drywall or sheet metal. It was used by US Air Marshals on aircraft to avoid decompressing the aircraft.

Shotguns can also be used, which fire bullets and hollow bullets. Any projectile that spreads the impact over a larger area will have less penetrative power and still be an effective round of close combat.

The downside is that the reduced punching capabilities of these rounds mean they are ineffective against body armor.

In the explosives department, traditional fragmentation grenades and anti-tank weapons were avoided. Concussion grenades that kill by explosive force alone could be used, but can cause minor punctures. Stun grenades and all types of gas, smoke and chemical grenades would also be safe.

Small penetrations of the pressure seal would be used to the advantage of the attacker. Safety would require small punctures in the walls not to grow or result in explosive decompression (sorry Hollywood, Mythbusters put on a whole show on this). This could be used to the advantage of the attacker.

If defenders lack breathing equipment, an attack team could be equipped with breathing apparatus that doesn't even have to be a spacesuit. You would deliberately make small breakthroughs in the outside wall to let the pressure fall. The defenders must now withdraw, surrender, or pass out. Once the oxygen pressure dropped to levels enough to incapacitate but not kill the residents, the engineers would quickly stain and repressurize the area. Medics would take care of the civilian population.

Even if the defenders have respiratory protection and large numbers of civilians, a siege tactic can be used. Surround their habitat, cut off air and water supplies, puncture the outside wall to relieve pressure (again, low enough to pass people out, high enough to keep them alive), and wait. Depending on how good your emergency care is, it can take a few hours or days before you are forced to surrender or pass out.