The USAF is looking for a 2000 lb missile replacement for its 5000+ lb guided free-fall bombs for bunker busting and the like, to quote Shrek, I think that someone is compensating:

Penetrate faster, harder with new AFRL weapon

……………

An Air Force Research Laboratory fact sheet with a 2011 time-stamp for public release approval tells us that a 2,000lb-class weapon with 5,000lb-class penetration capability could be available within three years.

“Future fighters will be able to deliver bunker-busting capabilities currently associated with the bomber fleet,” the fact sheet says.

I found the fact sheet for the High Velocity Penetrating Weapon (HVPW) in the AFRL munitions directorate booth at the Air Warfare Symposium a few days ago. The document reveals the USAF has shifted its focus on next-generation penetrator technology on a couple of different levels.

The folks at the USAF do seem to spend a suspiciously large amount of time talking about “penetrators”, don’t they?

BTW, running the numbers, the kinetic energy of a 2500 kg system at 300 m/s (about 650 mi/h), is 112.5 MJ, so for a 1000 kg system, you would need a velocity of only (475 m/s) 1800 m/s km/h (1080 mi/hr) to get the same kinetic energy.
(added correction in red  D’oh!!!)