Glocks are my preferred for duty/defense. Pick a caliber you wish to shoot. I use a 40 S&W and am looking hard at a 45 acp for accuracy and different recoil impulse but really like the 40 S&W. Choose solid ammunition from Golden Saber, Gold Dot, Federal HST, ect.
Shotgun-Remington 870 or Benelli would be my choices. 12 gauge is the standard but a 20 gauge would work fine also. Love the Federal Flite Control Wad with 00 Buck or any brand thats reasonably accurate with slugs. I used Remington slugs and shot out to 75 yards with a bead sight and managed to hit a man size silhouette without issue.
M4-I use Stag with anything from 55-62 grain ammunition. I also like the bonded bullets for defense use.
AK/SKS variants are another option. My buddy who is a combat vet gave up on the 5.56 and went with a AK variant after being shot at by the caliber. He was, personally way more impressed with it then the 5.56.
308 Carbine would be LMT MWSE or Armalite for that caliber.
