Ditto here. Don't bet your life on a sub-par weapon!
I'd recommend a nice, used S&W revolver. They can be found quite easily and many look about brand new because their owner was a middle aged man when it was bought decades ago . . . and it was his nightstand gun. The widows sell 'em every day to the pawn shops and gun stores all across America!
Here are three revolvers I use a lot for concealed carry and/or "car guns" when on the road. Each has a specific specialty, and all will get most jobs done well anyway.
The top one, made in 1980, is a chopped barrel S&W .45ACP revolver that uses .45 automatic cartridges in moon clips. All rounds go in, and all come out together still attached to the clip. Incredibly fast and easy to reload. It is my main car gun. If trouble ever comes my way, this is the gun I want in my hand, over all my other ones. I've won a lot of handgun matches with this incredible revolver.
I'll enclose also a photo of the little carrier I use with it to carry various types of .45ACP ammo for car use. Some rounds are good penetrating glass and car bodies, others are best for self defense, etc. I'm confident with this gun out to 100 yards . . . all ya have to know is how high to aim to drop the bullet on into the target! This comes with practice.
At about 38 oz. though, it is much too heavy for your stated goals, but I wanted to show you a good "car gun" that has big, easy to see sights and enough heft to help when you don't have to carry it on your person all day.
The second gun down is a steel framed little J-frame snubbie that I got last year. It is a 1964 Model 36 in .38 special. It is a great little gun that is extremely accurate. It is a good concealed carry gun, and also a good, accurate self defense gun! At about 23 oz., it is on the high side of your weight goal. Then again, the weight reduces felt recoil . . . allowing faster follow up shots under stress . . . and making it a whole lot more fun when you are practicing vs. the lightweight guns!!!
The bottom gun is another J-frame, a blued aluminum "Airweight" Model 37. Only 15 ounces, it is the ultimate weight and size for a "pocket carry" CCW firearm. It is my "always gun . . . usually in my front pocket in a pocket holster. I got it this year . . . from a widow. She outlived three husbands and the gun was husband #2's nightstand gun. I don't think he ever shot a box of ammo out of in. It was made in 1971.
Being a lightweight revolver, it does kick . . . though you will never feel the kick if you are ever firing it under the stress of self defense!
In any event, invest in a good used S&W. It will only appreciate in value in upcoming years . . . and last you your entire life if you take care of it!
T.