The US556 is an Average-condition carbine sold at Hot Springs from Trust level 3. It is reliable from medium to long range and takes a 50-round magazine upgrade. It is the best buyable primary in the north.
Build Trust at Hot Springs to level 3, then buy it and the bigger magazine together. Short on credits, grab the one in the military truck near Iron Butte, but it will not stay in your locker.
It handles human camps, Freaker packs and early Hordes. Range and accuracy let you fight from further back.
The MWS is cheaper but has less reach. The IDF Pup from Horde Killer is better in every way once you get it.
.22 Repeater
The .22 Repeater is a Poor-condition primary rifle you unlock at Tucker's Hot Springs camp. It fires fast and its ammo is everywhere, but each shot hits soft. Use it for early Swarmer packs, then replace it.
Combat Shotgun
The Combat Shotgun is a Military Spec pump-action shotgun sold at Hot Springs from Trust level 3. It hits hard with a tight spread and holds 9 shells. It is the best buyable pump gun in the north.
Frag Grenade
The Frag Grenade is a military fragmentation grenade you cannot craft. Hot Springs, Lost Lake and Wizard Island sell them from Trust level 3. Use them on human groups behind cover and on tight Freaker packs.
Lil' Stubby
Lil' Stubby is a sawn-off lever-action shotgun that fits the sidearm slot. It comes in three grades, Poor, Better and Pristine, each sold at a different camp. As a sidearm, you can fire it from the bike.