"Could you go to the North Plaza and meet up with Cletus, the gun shop owner? I'd like you to get him to help us if you can. If we can get Cletus to help us, then we'll be able to buy weapons. That would be good for you, too, right?"
Frank arrives to the Huntin' Shack to find a fellow survivor trying to reason with the gun shop owner. The owner refuses to let the two men come any closer and shoots his shotgun as a warning. James claims that he just wants some guns so he can survive. Going against Cletus' warnings, he advances towards him and is killed with a buckshot to the chest as a result. James flies out of the store and Frank is left alone to battle Cletus.
After Cletus is tired out from the gunfight, he stumbles out of the store into an undead James and is killed, leaving the gun shop empty and available for Frank to take weapons.
In Chop Till You Drop, Cletus does not have to die. Instead he will agree to sell you guns, ammo, upgrades, and books, that is if you choose to save him. In Chop Till You Drop, completing The Gun Shop scoop with an S rank and saving Cletus will allow Frank to take on the scoop Gun Shop Standoff.
There's no perfect place to hide from Cletus's shots. It is best to stand behind a Store Display for moderate cover and wait. Cletus must reload after six shots. When he does, step out and shoot. Duck back behind a Store Display as soon as Frank shots two or three times. Repeat this until Cletus is dead.
If health is needed when Cletus reloads, hop the counter and grab some wine.
Sniper rifle and barricade
Quickly hop the counter and grab a sniper rifle. Grab a store display as Cletus reloads and drop it next to the one near the counter. Take cover again and repeat the process each time Cletus reloads.
Green propane tanks
Many of the zombies in the North Plaza are pushing the green propane tanks. Carry one of the green propane tanks into the shop and throw it behind Cletus' counter, then shot it. Alternatively the propane tank can be used as a barricade like the store display. By staying on the other side of the propane tank, Frank can jump behind the counter without getting body slammed.
Find a Sub-machine Gun or handguns from the zombie cops. Trigger the fight and then run back outside the shop. Open only one of the doors to the Huntin' Shack, and hide behind the wall next to it (opening the left door seems to work best). If Frank stands at the edge, Cletus will find it difficult to hit him, but Frank will have a clear shot when Cletus moves over far enough. If Frank runs out of ammo, there's usually a zombie cop in the area near the shack.
Hand-to-hand attacks against Cletus should only be used as a last resort. If Frank jumps over the counter, Cletus picks Frank up over his head and tosses him back over the counter.
With a small chainsaw, charge Cletus at the beginning of the cutscene. When he reloads, rush him again and chainsaw him. Don't hop the counter or Frank will be body slammed.