Hi LostintheOzone,
The Chief's Special ain't a target handgun. It's a belly gun. It doesn't need sights. It is a close range handgun. It's a one threat handgun. If you had the extreme misfortune of confronting more that one bad guy while armed with only a Chief, may God be at your side. Keep in mind that bad guys rarely do bad things alone. If you ID one bad guy, look for others. A Chief holds five rounds and takes a full rotation of Earth to reload another five of what I consider bare minimum self-defense rounds. +P .38 Special rounds aren't special. May God be at your side should you have to reload any revolver at night while a bad guy is putting rounds on you.
I own a couple Chiefs. I love 'em. But I don't trust them to save my life. They're a neck and up gun meaning that if you don't connect with a threat's CNS at the range of their intended use, you're likely to take bad guy rounds, which ain't good. Without a CNS hit, a threat can soak up a lot of lead before he becomes incapacitated. The longer he's vertical, the more time he has to schedule your corpse for autopsy.
It's a very wise idea to get the heck outta a bad guy's sight picture. That means you gotta shoot and move. If you were stationary, you'd hand a bad guy a very good target of yourself.
Please indulge me: I've been able to carry a concealed handgun since 1982. I've carried quite a few, including a few duty handguns. You already have what might be the best CCW handgun: Sig P239. A P239 chambered for .40 S&W is the only handgun I'll carry; however, I can't tell you the last time I've carried a handgun on me.
You're right: the P239 is about 10 ounces heavier than a Chief. There's good reason for that weight. Recoil of a self-defense handgun must not take its muzzle off of a threat. Realigning sight picture is a tactical disadvantage. I can put 8 180 grain rounds in the important part of a silhouette at 21' as fast as I can pull the trigger. The added weight of a P239 facilitates keeping its muzzle pointed at what it oughta be pointed. I've fired the FBI Load out of a Chief, which might be the best round for belly gun self-defense. From a lot of experience, I can tell you that it's not easy to control a Chief with the FBI Load.
You can reload a P239 inside a couple seconds, which is a definite tactical advantage.
Here's my advice, which is nothing more than opinion: buy an excellent quality holster for your P239. It'll make carrying it a whole lot easier. Then buy a Chief because they're extremely cool handguns.
The Chief Special deserves its own category on this forum. It's an American icon. My guess is that after the 1911-A1, it's the most copied handgun ever produced.
BTW, have I mentioned that the Chief's Special is an extremely cool handgun???
We need a dedicated Cheif's Special category on this forum.
BTW, when I do shoot a Chief, it's at no farther than 10'.
One more BTW, in a perfect world, I'd carry a full-size 1911-A1 with 230 grain ammo. But then again, in a perfect world, I wouldn't need to carry a handgun.