Keltec SU16A is an excellent example of .223 “light rifle” with 18.5″ barrel and long sight radius. Tech Sight peep improves on factory with repeatable adjustments, sight radius extended to 18.75″ and two apertures for short/long range. With M855 (62gr) ammunition, the lower aperture gives 25/300yard zero and the higher aperture just over 450 yards. This covers the realistic effective range of the rifle/cartridge combination for defense or hunting.
At five pounds, SU16A fits the niche originally targeted by M1 carbine — with much extended range and improved ballistic performance. The newest iteration shown here have a metal front sight tower with protective wings instead of the hood, both for better durability and improved sight picture.