What is your experience with round nosed ammo? Have you ever shot anyone with it? Have you ever been shot with a round nosed lead bullet? Is your only source of information what you have read on the internet or in gun magazines? My uncle was a cop and killed one man while on duty. He did it with a S&W model 15 loaded with the issued RNL ammo. The attacker was killed on the spot. He never moved out of his foot prints.
Not just gun magazines. Back in the 70s, I studied the Justice Department study of handgun ammunition while working for the NRA. And though the study was faulty in a number of areas, it wasn't faulty in regard to the round nose bullets, which it pretty much panned.
The study's authors interviewed police departments and the military, and the .45 auto in World War II and Korea were pathetic. They would kill, but not quickly. And it doesn't make any difference if you're talking about a .38 Spc or .45, round-nosed bullets just don't usually take people down. I had a friend who came ashore in the Philippines on the same beach MacArthur had just a few days earlier. He was expecting no trouble, but he said some little guy came running out of the jungle screaming his head off and wielding a machete. He quickly drew his service .45 and shot the guy square in the chest. "The guy kept coming as if I hadn't shot him," my friend complained. "I didn't have time for a second shot, so I used the barrel of my gun to crack him over the head. And the amazing thing is," he told me, "the guy survived!" He didn't put the blame on his ammo, though; he blamed the .45 and never had a good thing to say about it for the rest of his life.
Also, there was the celebrated case in New York where a police rookie and a sergeant both emptied their revolvers (with round nosed bullets) into a towering bad guy. He died, but not before killing the sergeant with his knife. The bad guy, apparently a street person, eventually bled out. In some places, cops are taught to shoot, and, if necessary, run or prepare to physically engage their adversaries. In this Furgason mess in Missouri, if Wilson had not fired his pistol when he did, Brown would have killed him by physically taking the gun from him and using it on him, or he would have killed him with his bare hands. Better to shoot and disengage than to engage and die.
I wouldn't use round-nosed bullets for defense. And, actually, even 9mm FMJ is better than either the .38 or the .45 FMJ. The military guys I've talked to said they need the firepower and the penetration more than they need a big hole in the end of their guns. To me, that's sayin' something.