If you upgrade an Aeron 25mm minigun to level 98 heavy (at a cost of around 220,000y)its attack power raises to about 1000. If you raise it one more level to level 99 heavy, its attack power will be 17,525 but it will cost 6,700,000y. Another downside is its ammo capacity decreases from 94 to 6 but one shot should destroy any sv.