Started life as a complete Bushmaster rifle, swapped out the original 14.5" barrel for a 16" Colt Hbar and added a LarRue 9.0 handguard later. There are some cosmetic dings from being used like a rifle should but everything functions 100%. About 500 rounds through the barrel, maybe 1000 through the upper. The Colt barrel originally had a standard FSB that used taper pins. The taper pin holes are covered by the YHM low profile gas block. The the set screws from a previous gas block(before I owned it) dented in the taper pin holes somewhat. It doesn't seem to hurt function or accuracy whatsoever and I think you could still easily attach a taper pin FSB without a problem but I wanted to give full disclosure. Feel free to offer up trades but no goats or freezers fer cryin' out loud. Upper receiver and BCG/CH are sold. Barrel and LaRue rail still for sale. $200 each OBO.