Several of our own (respected) members have seen the occasional BM rifle in the hands of a deployed serviceman (all Army IIRC). The actual amount of rifles purchased may be smaller than 4,000, but even that is a drop in the bucket compared to the entire number of rifles in service just by the Army alone.
But, what's the big deal anyway? Everyone knows that those rifles were a one-time, off-the-shelf buy during the Desert Shield build-up when Colt couldn't supply the volume of new rifles that were suddenly ordered during those months (who could blame them, when their orders probably increased by a factor of 20 in a month or two). It's not like anyone is suggesting that BM ever had a "traditional" contract to supply rifles on a regular basis.
And the other side of the coin is this: Bushmaster has supplied the vast majority of rifles to the Personal Security Contractors that are currently in Iraq & Afghanistan. Those PSCs are nearly all former military, with a high percentage of "advanced" infantry training, and they have certainly seen their share of gun battles. There have been no complains about their rifles beyond normal wear & tear, and I think we all know that conditions in Iraq especially are about as difficult as it gets. So, it would seem that, military contract or no, that Bushmaster rifles are up to the rigours of "real war."
-Troy