Advantage of miniguns being military standard?

Question

I'm writing a sci fi fiction based on mass effect, different from the series though.

In it I've made humans terrified of an alien invasion/genocide so they focus on firepower/rate of fire or both. Since ammo is no longer an issue (shoots sand grain sized bullets at light speed) and only cooling is.

Would an army where most soldiers (not all but very common) use light weight miniguns with a backpack cooling system. What would that be like as an army? Pro's and cons? Remember ammo is not an issue and weight is lowered but not gone.

The army I wanted to use overwhelming firepower, shock and awe style combat and have had 70 years or so of focusing on weapon design.

Answer 1

There isn't a large army, or most missions are solo missions.

If there aren't many other people to worry about accidentally shooting, and it is likely that you are going to be alone and swamped by aliens in an invasion, everyone may have a minigun on them at all times. I imagine they will have a pistol or something else for more standard usage.

Answer 2

Perhaps. Your call.

When human infantry fights human infantry, with halfway modern firearms, on the offensive they tend to split into different sub-units for fire and maneuver tactics. One sub-unit fires, to make the enemy take cover, the other sub-unit takes the opportunity to maneuver into a more advantageous position, then the roles switch. For an overview, look at chapter 3 of this US Army manual.

So there are three requirements for an infantry weapon.

• It has to do enough damage to affect a typical target. The speed of yóur grains takes care of that.
• It has to come with enough ammunition to keep up suppressive fire. You've taken care of that in your setting, too. In the real world, consider the switch from 7.62mm or .30 battle rifles to 5.56mm or .223 assault rifles and carbines.
• It has to have a sufficiently high rate of fire. Compare Napoleonic or American Civil War era infantry formations with the slaughter of WWI.

Put two weapons next to each other. One is the minigun, with a high rate of fire, near-infinite ammunition and damage, and the need to carry a backpack cooling system. The other is a single-barrel variant, also with near-infinite ammunition and damage, but with a somewhat lower rate of fire due to to the weaker cooling system.

How accurate are both weapons? If the grains move at close to lightspeed, do they have time to be affected by wind or whatever? It makes little difference if a target is hit by one grain or ten. Point against the minigun.

Or could the minigun deliberately incorporate a 'shotgun effect' where a burst spreads a little? Point for the minigun.

Answer 3

Terrifiedness does not necessarily lead to rational weapons design choices.

Pro: Your weapons companies have delivered what the politicians promised to their terrified constituents - a minigun which shoots an all-destroying hail of light speed sand. In action the frictional effect of these grains on the atmosphere would produce tongues of flame tracking the course of the projectiles. Things in front of the guns disappear in a shimmer of hard radiation. They are awesome, these guns. It took a while to design in an awesome noise to go with, but now they have that too. Taxpayers happily paid the extra to produce many of these technological marvels so that every infantry man could have two.

Cons.

1. The grunts have to carry the two miniguns because that is what the bosses want.
2. The grunts have to shoot these guns when the cameras are on because the folks back home love it.
3. The guns are scary and hot and dangerous and produce a lot of hard radiation, as well as the tongue of fire which points back to the person shooting the minigun.
4. The awesome noise is deafening at close range but it is not hard to hack.
5. Standard issue weapons from a generation (or more) prior are much valued and grunts are allowed to carry and maintain their own.
6. In battle, one soldier is often designated to carry all of the light speed sand miniguns for his squad which means he may have 10 or 12 on him. Often a very large strong soldier is included in the squad for this purpose. That frees up the rest to fight unencumbered using their old guns, or weapons captured from the enemy. The big guy passes back the weapons once things settle down.