.308 semi-auto rifle: Springfield M1A
AK-47: I don't know, something reliable and durable, russian preferably
AR-15: High Quality, possibly LMT or Colt
12 gauge shotgun (pump, or semi-auto): Mossberg 500
.22 rifle (semi-auto, bolt-action, or lever-action): Ruger 10/22
.22 semi-auto pistol...