The challange of it.If you shoot it well enough and use a bullet that penetrates deeply enough (the 180s should do the trick), I see no reason a .40 wouldn't kill a deer at close range. Be prepared to chase it down, though. Most hunting authorities recommend rifles that produce a minimum of 1000 foot pounds of energy for deer. The little .40 produces less than half of that.
Is there a reason you are opposed to using the 870 with slugs? You'll have greater range, more power, and a gun that is much easier to shoot accurately than a .40 caliber pistol.
Just saw this post......I know I know......resurrected from the dead. But, the challenge of it is fine and dandy, just make sure that you kill the deer and retrieve it!!! If you are going to hunt, it is your duty as a responsible hunter to make sure that the method of which you choose to harvest the animal is more than adequate to do so. Very irresponsible to hunt with inadequate gear....just for the challenge of it!!!The challange of it.
So even this guy might have a chance to take one?Come up here, to where we live. Not only have we a veritable plague of deer, due to the lack of predators, but also they're so tame you could walk up to one and strangle it with your bare hands.
If you just had to insist upon shooting one, you probably could stop seven yards away and politely ask it to turn broadside to you, to make the shot easier. I'm certain that any of our deer would comply with such a polite request.