VR
Depends on which bit of (what was) FRES you mean...
A400M was never scheduled to carry the light tank variant (what was known as MA-med armour) which was always planned to come in in the mid forty tons with armour, bullets and gas.
You'd be surprised what the difference in weight is between the light armoured and the full armoured versions. I await correction, but not sure that the Mastiffs et al in theatre use the full armour fits; the reactive armour isn't on but the bar armour is? This is all open source by the way!
A400M is well capable of carrying the other versions. Not sure you'd be able to drive off and fight, but you couldn't do that off a C17 either and you'd have no chance of putting that weight on to a strip off a
UK C17...
Don't think the airdrop of 30t plus is a realistic option in a single load...!