Now THIS is cool

[Del Arroyo]

Heres an idea... mirrors! ;) Id like to see what happens when I fire my reflective armour coated missile at your fortress... good luck! :)

No mirror is perfectly 100% reflective. Whatever energy isn't getting reflected is heating/burning up the target. So with very powerful lasers, mirrors could offer some protection but not immunity. Depending on the reflectiveness of the mirror, the range of frequencies it reflects, and the frequency and power of the laser, the mirror could be melted through in no time.

DA

[Del Arroyo]

Also note that any minor damage to "mirror armor" caused by heating would likely snowball rapidly into catastrophic damage. The imperfection would reduce reflectiveness, causing more heating energy to be absorbed, causing further imperfection, exponentially.

DA

[Red Harvest]

Big problem with lasers would be little things like smoke, dust, rain, fog, snow...pretty much anything that blocks line of sight or scatters the beam.

I also wonder how you could maintain a bead on the same point on a rotating round? And would it matter if a round was a kinetic energy round instead of high explosive?