There are HBAR versions of the AR15 from just about every manufacturer. As mentioned above, they are marked HBAR in different spots on the rifle itself. A few manufacturers don't even mark the HBAR nomenclature anywhere (i.e. RRA), but they are still heavy barreled rifles. Remember, Heavy BARrel means a heavy profile under the handguards, from there forward it can have an M4 (i.e. RRA or Colt 6920HB) or straight profile. There are a couple shops that I know of who know the law well enough to abide it (sale of "non-regulated" HBAR's to 18 year olds etc.), but I'm not here to name drop. If you fail to find a shop on your own, IM me for contact info and I'll help you as best I can.