Rifle is good basic material for building something unique.  What I've had to do to make me happy...

EO-tech Halo-sight directly to the Picanny rail. Perfect cheek-weld height.

Modify stock slightly to accept BM's rubber recoil pad and added (2) forend sling swivels, (1) on the side for the sling and (1) on the bottom for a Harris 6" bipod.  Mlitary style sling wouldn't fit around the butt with the recoil pad.

Got a Jewell trigger (small pin) coming in a couple days from Georgia-Pacific.  Gonna set it 2nd stage 3lbls, 1st stage 1lb.  The factory pull feels like 6-7lbs and that doesn't mix well with 4.5lb rifle.

Laser-Lyte clamped to the top of the barrel tight up against the forend. Excess coiled cord tucks inside hollow section in the end of the forend and the pressure pad velcros to the side of the forend. Perfect.

Having installed an larger bolt release button from Wilson Combat for single shots from a bench. Also got the single round mag follower.  Already has an ambidextrous safety for us "lefties".  Shooting lefthand from a bench about 1 out of 10 empties grazes my cheek.  No concern.

Bushmaster now has a new snap on threaded adaptor that replaces the current snap on muzzle brake so you can use any pre-ban or post-ban flash-hider or suppressor with the common threads.  The Carbon 15 is notorious for muzzle flash with certain loads, I read.

Haven't done any serious Carbon 15 shooting yet with a proper scope but the factory said M.O.A. is attainable.  Always seems to take me about 6 months to assemble a rifle, handgun (KImber 1911), 10/22 Ruger, SW 3913, cars, boats, ATV's, motorcycle, house, etc. that suits me. ....and then I'll sell it for a loss and start over again.  Jeeeez!