Hello,
The search for meteorite fragments now seemed fruitless, because computation of the explosion parameters, together with the nature of the geophysical records, revealed that the density of energy at the moment of the explosion was extremely high.
http://www.galisteo.com/tunguska/docs/
Did you factor in eyewitness accounts?
Witnesses in the town of Kirensk and nearby towns at the same distance recollected the fireball flashing across the sky in the following terms:
"A ball of fire...coming down obliquely. A few minutes later [we heard] separate deafening crash like peals of thunder...followed by eight loud bangs like gunshots."
"A ball of fire appeared in the sky... As it approached the ground, it took on a flattened shape..."

"A flying star with a fiery tail; its tail disappeared into the air."
The initial explosion occured at an altitude of 5-5.8 kilometers with several more low-altitude explosions (bangs like gunshots).
see ya, VINCE