Originally Posted by
Dannix
That was 35 Remington. Well, you'd both made some excellent points, so I couldn't remember, and I was just too lazy to go back and look...
Concerning momentum, the optimal projectile weight range a cartridge can accommodate is the real factor in choosing mass and velocity if maximum (or near maximum) momentum is desired. If velocity cannot be gained directly proportional to the sacrifice of mass, or mass gained directly proportional to the sacrifice of velocity, then momentum is lost. Except, let me re-emphasize one point I made above, plus make a new one:
First, this is assuming you think Momentum is the deciding factor in stopping power. I do not. I used to think it was the best of the flawed methods out there, but once I started seeing real gunshot wounds and read some of Fackler's work, I tossed Momentum on the trash heap with all the other comparitive measurements.
Second, when it comes to momentum, the part that I found most objectionable / least consistent with real life, is that I've found bullet construction / deformation / interaction-with-target-medium to be of greater significance to overall penetration than velocity. I would say somewhere between 1.5 to 2 times more important, but that is only an average, meaning there are cases where it would be above or below that range as well, so it's not predictable. (Again, why we don't have a meaningful and proveable stopping power LAW -- only theories.)
So 35 Remington was right -- except if you're only working with a constant given cartridge, there's not a lot of wiggle room to play with. Take that nylon ball in 22-250 -- good luck trying to recoup the loss of mass with velocity to maintain near maximum momentum. (Of course nasa's goal was to test space craft, not to try to compete with a rail gun design). And of course the medium must be considered, as mentioned. A faster moving ligher weight may have the same momentum, but will be more likely to be deflected, sending that momentum where you don't want it. Also lower sectional density projectiles are draggier, which will manifests itself more at both faster speeds and bleed off speed more quickly on the way to the target and once in the target.
All of this is correct. But, first, take into consideration what I said above to the detriment of Momentum as a stopping power theory, and then take into consideration that we're talking strictly within the confines of the 32 S&W Long (which I think you are doing with your comment I bolded directly above). That's why I said at least a 100gr and better-still a 115gr ("or heavier" was implied) for Molly's uses. There DOES come a point where we go so heavy in weight that a reasonable velocity just isn't there as well. This is particularly a problem with a small capacity case or a case which is chambered in older firearms and so has pressure limitations. -- And, our poor 32 Long we're working with is saddled with BOTH...
I'm willing to guess that was a JRN. It may have been, but I can't remember, and I'm too lazy to go find the photos, and I won't put out speculation on it. I wonder that if the projectile was a FN it would have penetrated rather than deflected. That said, if the projectile was a good deal heavier than .32ACP spec, as Molly is planning, I would postulate that even with the same deflecting force encountered the heavier boolit would penetrate, particularly with a FN, simply due to inertia.
Concerning .32ACP as a minimum for consistency, I would concur except perhaps with a very unusual, unconventional design. Did I say that? :mrgreen: What I really said is that 32 is marginal. What I meant by that is that sometimes it works and sometimes it doesn't. That's why I said, for me, the minimum is 35-cal. (because I want something that reliably always works), and I want the velocity combined with bullet SD that is provided by 9mm and 38Spl., but I also said that with certain proven-effective specialty bullet designs (such as the Hornady Critical Def.), I'd go with lower-velocity and lighter bullets (lower SD) to the point of a 380. Luckily, there have recently been some really small pocket autos in 380 that really make 32ACPs hard to argue for, IMO.
However, our friend, Molly, has a revolver, and that changes things a little. For example, you can get MUCH superior sectional density bullets compared to the 32 ACP. Personally, I think he's sacrificing some, because the gun-size is large enough with a 32 DA Rev., that he could go with a 380 and be better-served as far as defense, but in the same size and weight package. But, if he REALLY likes those 32 Longs and can shoot them well, there's something to be said for that too. (Hitting with less-effective bullets always trumps missing with a cannon...)
(I couldn't help but dream up a .308x10mm :mrgreen:)