hmmm, i think the weight specs on that colt might be wrong...
eta: i"m assuming the bushy's not an hbar.
Colt probally has a half-round BC, where as the Bushy has one that is cut back. Heavier buffer in the bushy?
Colt likes to screw the consumer market so it's probally made with half-assed workmanship.
Although I'm not a Bushmaster or Colt fan by any means, I would get the Bushmaster.
weights come from the respective web sites:
Trying to compare apples to apples.