I wanted to trim some weight from my 20" Colt HBAR so I sent the barrel to ADCO. They recontoured the barrel in a mid-weight configuration (~.74").
Since I had everything apart, I took the opportunity to add a LaRue free floating rail and an YHM flip up front sight.
I haven't shot it yet, but the balance feels much better. I'll give you guys my impressions after I get the chance to shoot it.