One way to a cop's heart I guess is a cool cop T-shirt. My wife recently inventoried my closet and told me that I have enough T-shirts to outfit a battalion. I am guilty as well. The problematic ones are the shirts that could get you into a legal quandary.
The "kill 'em all" shirts may be cool on the range, but what happens if you are involved in a shooting and somebody recalls you wearing this vintage Wild West statement? You could have to explain your fashion statement on the stand without looking like a pistolero.
Use your head here and add some decorum. Besides legal issues, your choice of T-shirt could get you identified as a cop by some creep. You could get into a confrontation, armed or not; it may not be worth it.
I am not against wearing cool shirts in your off time, but the pistol packin', lead slingin', butt whoopin' statements do not speak well for what we want to call a profession in the public's eye. In the gym, on the range, or after hours with our pals they can be acceptable. Just watch your back in public; you never know who is watching.
Pistol Concealment, Not Pistol Bulges