I would offer what Barnes has been selling for years as a hunting bullet - hollow cavity bullets of gilding metal. FMJ is a combat round precisely because soldiers have to penetrate obstacles and body armor to get a hit. And, a hit is more likely to incapacitate the enemy, which diminishes his ability to continue the fight.
It's an error to require the enemy to fall down dead right there. First, because of the wide range of circumstances that will prevent it, which many soldiers and hunters have reported. A center of mass shot into the human being does not guarantee death. Second, that a soldier who is hit may still be capable of continuing the fight - humans react in a wide pattern of behavior, one who is mortally wounded may still be capable of combat, another who is lightly struck might disengage completely.
The effort in self defense ammunition it to STOP THE FIGHT. Full metal jacket has a habit of drilling small holes thru it's target with less cavitation, and has more retained energy that isn't imparted into the target. Therefore it's a general conclusion that FMJ won't stop as readily as a bullet designed to expand.
One of the early difficulties with AR15 hunters was the pronounced lack of expanding point bullets - FMJ was just whistling thru deer and the caliber was getting the blame for it. Load those up with expanding tip bullets and the results are largely different, as more knowledgeable hunters and shooters will explain. One important issue in this discussion is that more conservation departments have issued a regulatory ban on FMJ than 5.56. It's how the bullet is constructed that counts, not the caliber.
Missouri now allows any centerfire cartridge, which is a major change from the days where 5.56 wasn't allowed. And in the hands of an experienced hunter, game the size of elk can be brought down with 6.5 and 6.8 bullets. Those hunters were NOT using FMJ.
The expanding point bullets do the better job at stopping, and the same is true in law enforcement, who also have to consider the liability of the projectile passing thru and striking another citizen. The conclusion of many is that FMJ doesn't impart enough of it's energy into the target compared to expanding point, and it's the energy that causes the target to stop fighting, not the size of the bullet hole. After that, disrupted tissue could allow blood loss to kill the target, but that is a delayed reaction - it could take a minimum of 30-90 seconds for consciousness to be lost, enabling the attacker to continue the fight.
The OP requiring which FMJ round would be better invites the observation that for the use considered, FMJ isn't the best choice if at all. The real question is which type of bullet is the better stopper, and if the issue of being humane is included, then using FMJ is known to require further follow up shots to stop the attack. What's better, one shot, or half a dozen, at stopping an attacker?
It's a question that as been discussed on forum boards for over ten years, it takes insight and even training to get an idea of what is the real end goal. All too often the real question is which cartridge will knock down an opponent Hollywood style, and the answer is the two prop guys hauling away on the steel wire attached to the actor. If it can knock down a 165 pound human, Newton's laws indicate the shooter will be, too.
, but I am interested in the real world effects of each round. Thanks
My bug out bag is loaded with piss poor ammo. But that's only because I tested most of my good stuff and ran out of $$$.
