I just ordered a KelTec SU-16B 5.56 for $499 to use as my new home defense gun. My Inland rebuild Carbine will go back in the safe, as it is too valuable to me to loose to a burglar... The Kel Tec is a little over 4 pounds, 16" barrel on the B model I got, takes standard M16/AR15 magazines. It comes with two 10 rounders in the stock, but a single USGI aluminum 30 rounder will fit, also. With one 30 in the stock and one 30 in the weapon, that's a lit of firepower. The forearm fold down for an ersatz bipod. It folds in the middle for a survival/backpacking rifle, down to 25" long, so it will fit in my day pack. The one I had did just over 1 MOA from the sandbags at 100 yards.
I had one when the first came out an LOVED it. It is the only firearm that is as light and handy as the M1 Carbine to me. The new ones have 1/7 twist barrels, so I'll load it up with the MK262 MOD1 77 grain OTM SMK loads (2750 fps from a 16" for 1,300 ft lbs ME, and still almost 1,000 ft lbs at 200 yards.)