Does anyone know why they picked a number of 185 grains for the lightweight .45?
It was simple. Its just a 230 grain bullet with a hollowpoint in it. Using the same powder charge, naturally, the lighter bullet went faster.
There was a trade off there. You had the full metal jacket bullets which were used in two world wars and several wars in between and since and they worked. They would tend to shoot through people being full metal jacket.
Then the though process came along that the bullet needed to stop in its intended target and dump all of its energy in it, rather than wasting some by going through.
So, hollowpoints were tried. The bullet became lighter, but it created a bigger wound cavity and it seemed to really "stop" a little better because human being being soft targets couldnt take the "shock' as well as a bullet that passed through.
This talk of ligther bullets not being as effective is just semantics and in the big scheme of things it dosent matter. Yeah, lots of people like to discuss it, but fact of the matter is...if you are trying to shoot through barricades or you are concerned about pentetration of hard targets then you arent using the proper tools for the job, you should be using a rifle, not a handgun.
Second, anyone that needs to be shot, ought to be shot more than once, so that puny 185 grain bullet shouldnt be an issue.Three 230 grain bullets equal 690 grains, it takes 4 285 grainers for a total of 740 grains so when in doubt just shoot until the threat ceases and you'll be good to go and able to later debate the value of a light bullet vs. a heavy bullet on a soft target on the gun boards until the cows come home.
I have to disagree with you on some points. First off, semantics is about word choice and what we call things, so I don't see that it applies here. What we are talking about here concerns physics and physiology, and in that bullet weight
does matter. I'll agree with you that if we knew we were to be in a gun fight we would be using rifles. A pistol, of course, is an emergency tool to be used when you are caught without a rifle, or cannot carry one.
It has been proven that the single most important factor in stopping a bad guy is penetration into a vital target within the body; central nervous or cardioid-vascular systems. All else is secondary. The shock factor in a handgun bullet is negligible.
If a lighter bullet will penetrate to those targets it will be as effective. If it expands more and does more damage to that vital target it may be more effective. For instance, if it makes a larger hole in an artery so as to create a quicker blood pressure drop. If it expands and thereby fails to reach deeply enough to penetrate that vital target it will be less effective. Therein lies the rub. Lighter bullets of the same caliber tend to penetrate less. Giving them more velocity tends to make them expand more, and do so more rapidly. So, because energy is more greatly affected by velocity we get more energy dump into the body. However, back to rule number one, if that energy dump doesn't take place in a vital place in the body, it is not effective as a stopper. I refer you to the FBI Miami shootout which could have ended without further grief if one of the first bullets to hit Platt had penetrated another inch. It stopped a half inch short of the aorta.
The total weight of lead you put into an attacker, 3rounds of one vs 4 of another, doesn't matter all that much if it doesn't go to the vital targets in the body. In Miami, Platt had been hit twelve times before being stopped by the twelfth round. I agree one must shoot until the threat stops, but you'll have a much better chance of accomplishing that using bullets that are more likely to penetrate enough.
Anyone who hasn't read the full report and conclusions of the FBI shootout should do so. Also, learn about sectional density and how it relates to penetration.
Finally, please note that I am not saying a 185 grain .45 bullet is inappropriate, that
may be so, and would require testing to prove out. What I'm saying is it is less reliable because it is subject to more variables, therefore, I prefer to use higher weight-for-caliber (sectional density) bullets when I have the choice.