I just did the same, you beat me to it

I think the first link says the most likely:
"The original meteor, before partially disintegrating, may have weighed 510 tons!"
Although; how much of that weight could have been stripped without some Tunguska type event? Maybe some roche breakup first?

The search had lots of single line entries and most said it was 500 tons, but I think this one is the winner.
"Had it fallen at a slightly different angle, it would have destroyed much of the city and killed at least half a million people!"