Some people just don't understand safety.

[hardworker]

My buddy used to be really bad about handling a gun. I pretty much told him he was being an idiot in the way he handled it. He didn't got offended, and now he's much safer with one. So if he's a good friend, call him an idiot and tell him what he's doing wrong.

 

[twofifty]

TexasG, unless your irresponsible friend first takes a safe gun handling course and applies what is taught, once he acquires his own gun your safety and that of others at the range will be greatly reduced.

Since it will be buddy's gun pointed at you rather than your own HG, you will have much less authority to intervene: it will be HIS gun after all.

 

[Sevenfaces]

From what I have gathered, the idea of "If you think it might be a bad idea, it probably is." won't apply to this person.

Its very simple, explain to him that jerking around with firearms is dangerous, and stupid. If he refuses to take it serious, then just don't bring him around any, or while you're shooting.