From miniguns, they were. Rather damaging criticals for a weapon that does piece of shit damage against anything more than leather armor.
Fallout's miniguns are horribly broken because they don't work with the damage threshold (DT) of armour. If you have a weapon that throws out 20 shots, that each can only do a maximum of 11 damage, and you have armour with a damage threshold of 11 or higher, then you can only do damage on a critical that bypasses armour.
Seems pretty sillly to me, and biases the system in favour of single shot, high damage weapons.