Talk:.45 ACP

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[edit] The ancient debate about stopping power

A few changes I made: I read something about .45 being more effective than other loads "Because it knocks people down." Weither or not this was a poorly worded discription of stopping power, or weither or not whomever wrote it was misinfromed, I removed it because bullets dont really knock people down like in action movies. --ThegunsofNevada 23:10, 12 January 2006 (UTC)

Anybody out there qualified to fix this? I can see a few things I don't like. "Not effective against body armor". This is pretty silly, as this is true of almost every pistol cartridge. "Lacking accuracy or velocity at long range": This is a low-velocity cartridge, of course it doesn't have a lot of velocity at long range. I've not heard of it having a reputation for inaccuracy at longer ranges either; perhaps this is a criticism of the Army-style 1911 rather than the catridge itself? Also, references to hollowpoints mention "flesh-cutting" in more than one place. Are cuts really a wound caused by bullets? I thought they typically ripped and crushed flesh, rather than cutting it. Also, some hollowpoints being "legally available only to law enforcement": I thought this was a voluntary move on the part of some manufacturers due to possible public opinion problems. Friday 30 June 2005 04:32 (UTC)

Attempted to fix most of the above. Still not sure that discussion of politics of hollwpoint rounds belongs in the .45 ACP article specifically. Friday 2 July 2005 20:00 (UTC)

There are public perceptions problems with hollow points, not exactly centered around the .45 ACP round. I think the "Black Talon" bullet is one of those JHPs that are law enforcement only. Public perceptions are skewed because supposedly that the Black Talon was this horrible bullet that did significant more damage. However, arguably, the bullet is simply an JHP that does a good job at making sure the jacket expands at differing speeds and against target behind cover - I believe auto glass can drop about 200 fps from a bullet, severely decreasing many JHP's jacket expansion capabilities. One of the side effects of JHPs not expanding is that the bullets goes through the intended target, and may harm others behind. Indeed, under this light, the Black Talon, and subsequent JHP that's designed to expand well in varying speeds and more consistent penetration against target behind cover, are actually safer than JHPs of older designs. I would like to see the abbrevation ACP be expanded. I forgot what exactly does it stand for. Calyth

"Black Talons" were simply vilified in the press until Winchester pulled them. Then they omitted the paint and reissued them as Ranger SXT ammunition. There are, to date, no "LEO only" JHP rounds. --Mfree 17:46, 28 June 2006 (UTC)

    ACP stands for "Automatic Colt Pistol."
On the contrary, there are lots of LEO rounds. Take for example nearly all +P+ 9mm rounds; you can't buy them retail. They are designated for the law enforcement market, and must be ordered through a dealer which sells to law enforcement. Now there's nothing keeping that dealer from selling them to you, unless state or local laws prohibit it, but that takes the liabilty pressure off the manufacturer. Same thing with, say, Ruger factory Mini-14 magazines of >5 round capacity. The are marked LEO, but anyone (local laws permitting) can purchase them, IF they can find a dealer who will sell them. And if you don't believe that, look at:
http://www.winchester.com/products/catalog/handgun.aspx
Note, no Ranger SXT line listed. However, looking here:
http://www.winchester.com/lawenforcement/pdf/LEPDF/2006%20Poster_Front.pdf
you'll see that the Ranger line is all marketed as "Law Enforcement Ammunition". Firearms Tactical also notes that the Talon and Ranger SXT lines are LEO, only reaching the civilian market through secondary channels. scot 18:31, 28 June 2006 (UTC)
I'm sorry, I should have been more precise. There are no lines of ammunition that are banned from civilian purchase by federal law and hence restricted to LEOs. State and local laws are indeed found to differ. --Mfree 02:15, 9 July 2006 (UTC)
Nope, you're wrong there, too. Anything the ATF considers "armor piercing handgun ammunition" is illegal to sell to civilians, but can be sold to police and military or exported. See 18 U.S.C. CHAPTER 44 section 921(a)(17)(B). scot 15:03, 10 July 2006 (UTC)
Oh, and here's the ATF's list of what they consider AP handgun ammo, including 7.62 NATO AP and ALL steel core 7.62 x 39mm, and of course the original teflon/steel KTW stuff made for the Ohio highway patrol. http://www.atf.treas.gov/firearms/legal/armor.htm scot 15:08, 10 July 2006 (UTC)
Well just paint me purple and cover me in feathers, seems i'm having a bad factual day.--Mfree 19:22, 10 July 2006 (UTC)
Well, lucky for you I'm out of purple paint and feathers. Just take a deep breath and say "Scot is always right" and you'll feel better :). BTW, this discussion inspired me to write this, so some good came out of it. Maybe I'll overhaul cop killer bullet next... scot 16:09, 11 July 2006 (UTC)


I added a bit of perspective to this page today, trying to offset some of the POV and .45 worship that too often goes on when the .45 ACP is discussed. I added references to the some recent ballistic research.

As far as hollow points like the Black Talon "cutting like a buzzsaw through flesh" (I read that somewhere else, BTW), if a pistol round rotates once every 22 inches (eg, fired from a barrel with a 1 in 22 inch twist) and it penetrates 11 inches into tissue, it will only make one half of a revolution before it stops. Ergo, no "buzzsaw". This "buzzsaw" fallacy is too often perpetuated as knowledge by people who don't take the time to do the math.

The Black Talon was 95% marketing hype, and 5% decent design--it's been proven no more effective than any other high performance hollow point design of the same era, and the new Ranger is the same design with the points rounded off, and is no less effective. That said, your physics model is too simple. In reality, linear and rotational deceleration will be quite different, and further complicated by the fact that the bullet's rotation inertia will change dramatically as it expands. The upper bound, however, works out to be 1 turn at full speed rotation in the time it takes to decelerate to 0, so the correct answer is likely going to be somewhere between 1/2 and 1 turn.

Most wound damage by subsonic bullets like the .45 ACP is caused by the permanent wound channel, while supersonic bullets like the 9mm Luger do commensurately more damage by the temporary wound channel (cavitation) caused by their higher velocity. Gel studies show this conclusively.

Gel studies show permanant cavities and temporary channels--they say nothing about which does any good.

As far as the .45 being unable to defeat body armor, this is a proven fact, with documented cases of .45 ACP even failing to penetrate and deflecting off of windshield glass, due to its low velocity and large frontal surface area. This makes the .45 ACP a marginal round for police use, IMO as they may often have to fire into moving motor vehicles, a problem not often encountered by military forces, who will typically have longarms to deal with such threats. I did not mention this in the article, however.

Deflection has a lot to do with shape as well--if the bullet hits at an angle such that the tangent between bullet and surface is not close to perpendicular to the direction of travel, then the bullet will deflect. For equal deflection angles, heavier bullets will deflect less than lighter bullets at the same energy, because the heavier bullet will have more momentum. The best bullet for minimizing defelection would be plated Keith style SWC; it's heavy, not nearly as back-heavy and so more stable, and the wide, flat nose is going to keep the angle closer to parallel to the path. See this article, the section on "Brush-Bucking Calibers and Bullets".

My favorite story regarding poor penetration of the .45 ACP is the televised interview with an LAPD police supervisor who stated that, due to weapons changes brought about following the infamous Northridge bank robbery shootout, they were switching from 9mm to .45 ACP, which would make their sidearms "more effective against body armor"! I still laugh when I see this one. 9mm Luger bullets are demonstrably better able to defeat lower grades of body armor, and other obstacles like building walls and car bodies, than the .45 ACP. More simple physics.

Armor penetration depends as much on bullet construction as anything else, otherwise there would be no such thing as "armor piercing bullets". The WORST bullet type for use against body armor is an expanding bullet, because it is designed to deform and spread force over a wider area. This is exactly the opposite of an AP bullet, which is made out of very hard materials so that it doesn't deform. A .45 ACP FMJ with a tough jacket is going to be more effective than a 9mm JHP against armor, due to the higher sectional density and resistance to deformation. The .45 ACP FMJ will also be more effective against a soft target than a 9mm FMJ due to the larger permanant cavity. Granted, this is not an apples-to-apples comparison; a 9mm FMJ at 147 grains has the same sectional density as a .45 ACP FMJ at 230 grains, and at the same velocity they will penetrate armor just as well. However, if you do go FMJ, then bigger is better against soft targets--unless you want to get into the fragmenting 5.56x45mm vs. tumbling 5.45x39mm comparisions.

"Law Enforcement Only" ammo is implemented by manufacturers to allow police departments to avoid paying federal excise tax on ammo.

Then why isn't LEO ammo sold to civilians either a) less expensive or b) illegal due to tax evasion? Class I firearms sold to police go through the same distributors and same FFL holders that civilians firearms do, so they are paying the excise tax; why is ammo any different? I assume that the police can claim such purchases and get a refund from the Feds, so I don't see that it makes any difference other than for PR, like Ruger's refusal to sell 20 and 30 round Mini-14 magazines to civilians. scot 14:44, 17 October 2006 (UTC)

Hope this comment answered some of your questions, Friday and others. --NDM 07:34, 17 October 2006 (UTC)

[edit] More thoughts on ballistics, etc.

Scot:

I've read your comments and find many of your points to be interesting.

I agree with your assessment that most of the controversy surrounding the Balck Talon cartridge represents hype and hysteria.

I'm gratified to see that your calculations concerning the rotation of the bullet agree with mine to within one half of a rotation.

As far as gel studies go, I also agree that they serve as interesting models, but must be verified against actual experience. I do feel that gel testing offers information which may lead to valid inferences. I did not, however, state in my initial posting that my opinions regarding gel testing, and the significance of permanent channel vs. cavitation vis a vis wounding potential arise not only from gel testing, but also from having performed several hundred autopsies on gunshot victims. I do apologize for that oversight, as it would have clarified my position on this topic a bit.

I have seen that the pattern of wounding of bullets appears to change on somewhat of a continuum when viewed as a function of projectile velocity, with the nature of the wound changing significantly when comparing subsonic vs supersonic projectiles. Cavitation can indeed be a significant factor in the wounding ability of supersonic projectiles. This topic is quite complex and subject to many variables, and I certainly cannot do full justice to it here.

Your comments on penetration of body armor and deflection of bullets from obstacles ignores effects caused bullet velocity, which should not be neglected, as the behavior of objects in the supersonic realm may differ significantly from subsonic objects.

As for your questions about "LEO-only " ammunition: I am not a tax lawyer, so I do not know why the excise tax would not be paid upon resale. Perhaps the tax applies only at the time of initial sale to the end user, and not upon subsequent surplus sale. Perhaps people who do sell this ammunition are simply breaking the law. I do not know. I would comment that if police are exempt from paying the tax in the first place, then obtaining a tax refund would seem unnecessary. Your questions would best be answered by a tax expert, which unfortunately I am not.--NDM 07:35, 19 October 2006 (UTC)

The .45 ACP page says the following: "The U.S. Army had been using .38 caliber revolvers, and tested .38 caliber pistols developed by Colt just after the turn of the century. " It must be reworded to use the exact century. The century digit turned 6 years ago.

Severino Alvarez216.68.72.130 18:47, 30 November 2006 (UTC)

[edit] .45 ACP magazine capacity:

In the past, magazine capacity limitations existed with the .45ACP (such as the Colt 1911 with a 7+1 capacity), but I do not feel this is the case any longer. With weapons such as the Glock 21 (13+1 capcity), the Springfield Armory XD-45 Tactical model (13+1 capacity) and the new Fabrique Nationale FNP-45 (14+1 capacity), the issue of poor magazine capacities are a thing of the past.

Since this is not my article, I chose not to personally edit the material, but I leave it up to the original author to edit it as he/she sees fit. I think an inclusion about the fact that magazine capacities for .45 pistols meet and in some cases exceed 9mm capacities in certain models of pistols is a valid addition to the article.209.114.201.30 16:28, 2 December 2006 (UTC)

While this has been true for quite some time--I had a 13+1 Para Ordnance 1911 frame, with the extended 15+1 magazine, back in 1990--the widebody .45s have never had the popularity of the smaller calibers, because the grip is significantly wider and deeper. The .40 S&W, on the other hand, was designed to fit in 9mm length frames, and as a side effect, they generally stagger the rounds less to fit in a 9mm magazine well; this means that all that needs to change for a .40 S&W is barrel and slide--maybe just barrel and extractor. This all boils down to mean that, with very few exceptions, you can't compare 9mm and .45 ACP guns directly, since they're not the same outside dimensions. I'll take a look at the article and make sure that it makes things clear. scot 16:09, 4 December 2006 (UTC)

[edit] Capacity, cont'd

I agree completely that the ergonomics of the .45 caliber pistol frame may not lend itself to every shooter's hand size. With that, there is no contest. My only suggestion was to include a statement that makes clear there are options for high-capacity .45acp chambered pistols. I think the addition you made to the article makes that pleasantly clear now. All-in-all it is a good article. Good information.209.114.201.30 20:40, 7 December 2006 (UTC)

[edit] Bullet diameter

The article lists a nominal bullet diameter of 0.452 in. This is news to me. I reload, and have been loading 0.451" diameter jacketed bullets and 0.452" diameter cast lead bullets for several years. The vast majority, if not all, jacketed bullets sold for reloading .45 ACP are of 0.451" diameter. Similarly, I've seen and used cast lead bullets of both 0.451" and 0.452" diameter.

It would sure be helpful if the article mentioned the actual land-to-land and groove-to-groove diameter of barrels of .45 ACP firearms. I assume it must 0.450" groove-to-groove, based on bullet sizes. The rationale is that copper jackets don't deform as readily as lead, so you need a bullet only 0.001" larger than bore diameter to get a good bullet-to-barrel seal whilst avoiding excessive stress on the barrel - thus 0.451" diameter. Cast lead, being softer, requires a somewhat larger bullet (0.452" diameter) for similar performance.

Commercially-available jacketed bullets, identical to those used in .45 ACP premium self-defense ammunition, are invariably of 0.451" diameter, aside from a few manufacturers who bill theirs as being of 0.4515" diameter. I don't know how realistic a manufacturing tolerance of 0.0005" is for a bullet, and my dial calipers only measure increments of 0.001".

Is this a true discrepancy, or have reloaders and jacketed ammo manufacturers been using the wrong diameter bullets all these years? Or am I just being anal? 8) Objekt 05:07, 16 February 2007 (UTC)

I can't speak to your statements necessarily as much of what you say is self-research. I can only say that I got the info from the Lyman Reloading Hanbook, 48th edition (this is the book I get all the cartridge dimensions from). The dimensions listed in that book show a bullet diameter of .452" IIRC. I don't have the book handy at the moment, but I will recheck in the AM. Coincidently, this reference book also has groove-diameter info. I'll check it and post here tomorrow with what I find. —Thernlund (Talk | Contribs) 08:07, 16 February 2007 (UTC)
According to the handbook mentioned above, the diagram specifies a .452" bullet. Reading the near the end of the text, it has this to say...
"Groove diameters can vary from .450" to .453", but the shooter should not size cast bullets larger than .451" due to chamber dimensions."
The test specs given were for a .450" groove diameeter and a .451" cast bullet. I have no way to know what factory ammo size it, so I suppose I have no problem changing the spec to .451". I'll change it now. —Thernlund (Talk | Contribs) 20:17, 16 February 2007 (UTC)
All this is a bit weird, because although jacketted bullet diameter for the .45 is indeed 0.451 spec now, this is much closer to groove-groove diameter for the barrel, which is .450-.452. And perhaps that is as intended-- you want jacketted bullets to be made at groove-groove dimensions, and NOT the "official" barrel diameter, which is measured from land-to-land and ought to be *smaller* than this by several thousandths. Real pistol barrels, certainly those made in 1911, might very well not be nearly this precise, even from weapon to weapon. There's more than you want to know about "slugging" your particular barrels if you cast, which involves firing a soft bullet and then measuring IT to see what your barrel actually is like. [1]. I first started to laugh at the idea of casing bullets to 0.001" but apparently they can be cast now more accurately than weapon-to-weapon variation, even for military weapons made on modern lathe equipment, 100 years ago. SBHarris 20:48, 16 February 2007 (UTC)
Keep in mind that firing a bullet will obturate or swage it to fit the bore, unless it's grossly mis-sized or extremely hard. Also, as far as measurement goes, American firearms tend to go by the groove diameter, not the land diameter; this is why a .308 Winchester uses a .308 bullet, while a .303 British uses a .311 bullet. Of course this is complicated by obsolete trends, such as the .357 inch .38 caliber rounds, evolved from heeled bullet designs that acutally used bullets closer to .40 inches. There's also the .221/.222/.223 measures, changed to make the name more unique thought they use the same bullets; this survives into the present with the .480 Ruger, which uses a .475ish bullet. Also, slugging is generally done by pushing or pulling a soft lead slug through the barrel by hand, not firing it. When doing it by hand, not only do you get an undamaged sample (stopping a high velocity bullet with no damage requires lots of careful prep) but you can also feel the passage of the slug. Going from chamber to bore, you should never feel a loose section, the barrel should be cylinderical or decreasing in bore diameter all the way to the muzzle. scot 20:59, 16 February 2007 (UTC)
Thanks for the correction. I'd forgotten that the American practice of bore diameter measure differs from the Brit, and that neatly explains why the .45 official bore diameter so much more closely fits groove-groove. And yes, there's the .22 bullet foolishness. Apperently they are all the same except the rimfire which really is .2225 or something actually different from the others. Arghhh. SBHarris 21:15, 16 February 2007 (UTC)
Yes, this is one case where the American way of measurement (save for the heeled bullet leftovers) is actually much more useful; bore diameter is the most important bit, land diameter can vary a lot--just look at Marlin Firearms micro-groove rifling vs. conventional 6 groove rifling. .22 rimfire rounds and barrels can vary a lot in actual diameter, since the bullets are so soft; Lilja makes a .2215 rimfire, a "tight" .2200 rimfire, and .224 centerfire barrels. Also, firearms .17 caliber is .172, vs. airgun .17 caliber of .177. Of course, as odd as firearms measurements are, I still think the most idiotic system of measurement has got to be metric tire measures--if I want a wider tire, darn it, I just want to be able to say "Give me an 11.5x31R15", I don't want to have to go "I've got a 215/70R15, so to go up 20mm I need a 235, so what the heck profile do I need to keep that the same outside diameter?", and then trying to figure out the speedometer error at 70 mph when it turns out I need to get a 235/75 profile to get the off-road tread... scot 21:40, 16 February 2007 (UTC)
Thanks to everyone for mentioning a lot of stuff I never knew about. I just finished reading the article about heeled bullets. Very educational! --Objekt 04:03, 17 February 2007 (UTC)

[edit] Marshall Source?

Can someone please provide a link or citation to this "Marshall & Sanow" report concerning stopping power that is mentioned in the article? 209.195.164.34 17:21, 2 April 2007 (UTC)

I believe people are referring to Handgun Stopping Power: The Definitive Study. I have not studied the primary sources including this book, but people I tend to trust say that this book makes statements that are unsupportable based on the quality (or lack thereof) of the data set Marshall & Sanow collected. But it certainly has been a very influential book. (Me, I'm in the camp of Martin Fackler, some of who's papers I've read, all of which were are of high quality.) Hga 19:41, 2 April 2007 (UTC)
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