I bought a Bushmaster Pre-ban last year with a 11.5" barrel w/5.5 " flashhider on an A1 upper. Shoots great but I hate the loss of velocity. Bullets bounce off 1/4 plate at 100yrds while everyone else is drilling holes. I HATE that. So,new barrel or whole new upper? I think that if I got a whole new upper the old one will end up being a paper weight. Bushmaster is offering a new light weight 16" barrel w/birdcage flashhider for $180.00. I don't think I want the M4 because it's too trendy now. What would you do?

Re-barrel. You can probably recoup much of your outlay by selling your old barrel. I guess it's still good as you only complain about low veolcity.
Scott