Its stated as such, They have to close and orbit a Planet to Bombard it in the Fall of Trantor(Which was not Destroyed BTW but the planet's Towers where wrecked not melted or destroyed just wreaked)What reason do you have to think your weapons outrange Trantor weapons?
No he bombared it it was not DestroyedI believe the Mule destroyed a planet he thought the Second Foundation was based on
Because there are many diffrent was of Destroying a Planet, The ICS is solid numbers not "Destroy a Planet" with visable effects as we saw with the DS which had 60X the force nessary to Destroy a Planet if I remeber my Numbers Corrrectly(Its designed to Destroy Shielded Planets)At any rate, do you have any reason to disregard this evidence? After all, the "Uber Turbolasers" from ICS are never seen to fire in the movie, yet nobody tries to deny their power (okay, I'm sure some crazed trekkies do but they deny everything.)
Meanwhile we have "Destroy a Planet" but never SEE a Planet Destroyed and then we have Trantor Which was bombared by a Fleet yet very much survives...