Supersonic .45 ACP?

I figure if you took a big .45 bullet and made it supersonic it would be one of the most excellent defensive rounds.

Click to expand...

What's it matter, you can't out run it either way.

CWL beat me to it. I was going to say if you want a supersonic .45ACP then take a careful look at 10mm.

*Shrug*

Most folks consider that the 9mm round failed to penetrate sufficiently as being a problem with the 9mm round and it was not.

Click to expand...

This was not a chambering issue, or a defective round; it was that the performance model used to design the round/bullet did not anticipate the end-state scenario.

But in response to your statement:

As it turns out, the round performed to specs, and to the new specs that came AFTER the incident.

Click to expand...

I'm not sure on this. I was of the impression that the Winchester 115-grain Silvertip hollow points used by the FBI during the shootout did not, in fact, pass the test protocol subsequently developed.

The 9mm round used performed fine and they got the FBI's 12" of soft tissue penetration as required by the new protocols established after the incident (4-5" through the arm and then at least 8 inside the chest). Note that the new protocols did not call for passings through multiple soft tissue events as happened with Platt.

Click to expand...

I presume that the barrier tests that the FBI added (glass, sheet metal, etc.) were considered more rigorous than gel barriers. Dunno for sure.

The key here is that, as always, YMMV.

BlindJustice said:

yep sure does.... I was keeping it simple, should have asked
with the same temp and air density how much difference does
a couple of thousand feet make in terms of speed of sound?

I live at 2,500 feet, but the target range I shoot at is 2,000 feet
approx. lower, and it's always 10 or more degrees warmer
down in Lewiston ID

Click to expand...

Well, the cop-out answer is I don't know for sure, but I would say 10% higher? Only reason I say this is that I don't feel like cranking through all the math do get the precise number .

rbernie: useful info on the speed instability. What I wonder is how much impact on accuracy and bullet stability that this instability has?

Rbernie I will concede your point about the effect on bullets that are hovering around the speed of sound, in THEORY. In reality I have never seen any real degradation of performance in the rounds in question. They seem to have plenty of accuracy in most of the guns I've shot. As far as the FBI protocols, don't presume what I do and do not know please. I provided the test results to you and it seems you are not willing to entertain the idea that these loads, with modern bullets, do perform quite well. All your hyperbole aside, if someone chooses to carry the faster loads the SD of these loads is not so low that they will prove totally unreliable like you say. It just doesn't play out in reality as much as it does it theory. The real question is whether of not it makes enough of a difference that it is worth the extra recoil and muzzle blast over the 230gr loads and I think that is a personal choice. Personally, I like the 230gr +p loads in my fullsize guns and the 200gr loads in my shorter barrel .45s.

This is supposed to be the results for the Double Tap 185gr +p load through four layers of denim and 2 layers of cotton T-shirt. This load used the Gold Dot bullet which has always performed respectably in FBI tests through barriers. Personally, for self defense I don't think the wallboard, sheetmetal, and windshield tests are as important to us folks for CCW as they are for law enforcement. Almost 13 inches of penetration at .82" looks like a "good" load to me and I think that is what the original poster did ask about.

185gr Gold Dot JHP @ 1225fps - 12.75" / .82"

hmmm you might be able to make a sabot round. use a 9mm in a 45 casing and put lots of powder in it lol..... just a thought

Federal Hydra-Shok 185 gr. +p are rated at 1180...

Using an online Sectional Density calculator resulted in the following numbers. I don't know what you would consider high or low but here is how the lighter .45s compared to the 9mm and .40 loads.

cal/weight/SD
.45/165/.1164
.45/185/.1305
.45/200/.1411
.40/155/.1383
.40/165/.1473
.40/180/.1607
9mm/115/.1303
9mm/124/.1405
9mm/147/.1666

The 165gr .45 does have the lowest SD but how much difference does that .02 make? The lighter load in 9mm and .40 have almost identical sectional densities as the 185 and up .45 loads and many of the lighter 9/40 loads have respectable reputations as stoppers whether they meet the FBI criteria or not. How is that a .45acp load with a nearly identical SD is ineffective? It seems the slow and heavy crowd has a million reasons why you can't punch things up a notch with the .45acp but the arguments don't seem to hold up to scrutiny very well.