This AR-180B originally had a polymer lower receiver. However it has been updated with a NoDak SPUD AR-180 billet lower receiver. The polymer lowers can break from hard use so a metal replacement is a much needed upgrade. The receiver is threaded for AR buffer tubes however the LOP is still rather long even when the stock is fully collapsed. The AR180B can take any AR-15 style magazines so it is sporting a SureFire 100rd magazine. Ontop of the upper receiver is a QD scope mount with a Nikon P223 scope. The only thing it needs now is removal of the flash hider and threaded for suppressor.