Duke Missions

How do I concentrate on a particular body-part? Noob here and here is the mission.....

We got a cocky little a-hole on our hands who thinks he's tough. "Go ahead: shoot me," he says. "You think that's going to convince me to pay you back?"
I think he ain't gonna give me a single dime back whatever I do, so we may as well make his life misery. This one time when I was like nineteen I came off my bike and broke both arms. I had to ask strangers to help me pee and wipe and feed me. It was super embarrassing. I want him to feel the same way. Injure both of tankman3562's arms for me, so I can imagine him tryin to head to the can every time I feel a bit down.

Any help is appreciated...

I believe that it's random what body part you hit. You may have to attack the target multiple times to hit the correct body parts.

This. Use a pillow to maximise efficiency - it has high accuracy but low damage so you can maximise the number of hits made before killing someone.

Thanks y'all!!

Also, i find that knuckle dusters are a cheaper alternative if you can't afford the pillow.