Supersonic .45 ACP?


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Soldier0117
January 5, 2008, 11:31 PM
Does anyone know of some good jhp. rds. for a .45 that are supersonic? I figure if you took a big .45 bullet and made it supersonic it would be one of the most excellent defensive rounds.

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rbernie
January 5, 2008, 11:55 PM
You cannot get a 45ACP round to be reliably supersonic without making the bullet so light as to be unusable, given the pressure limitations of the chambering.

If it could be done, it would have been. :)

rbernie
January 6, 2008, 12:00 AM
You cannot get a 45ACP round to be reliably supersonic without making the bullet so light as to be unusable, given the pressure limitations of the chambering.

If it could be done, it would have been. :)

jon_in_wv
January 6, 2008, 12:49 AM
The speed at which sound travels in a given medium under specified conditions. The speed of sound at sea level in the International Standard Atmosphere is 1108 ft/second, 658 knots, 1215 km/hour. See also hypersonic; sonic; subsonic; supersonic; transonic.

Corbon 165gr +p - 1250fps
Corbon 185gr +p - 1150fps
Corbon 165gr +p - 1225fps (Pow'rball)
Doubletap 165gr - 1325fps
Buffalo Bore 185gr +p- 1150fps
Remington 185gr +p BJHP - 1150fps

There are a few other out there as well. If these aren't supersonic they are darned close. I believe the problem is that most of the earlier fast 45s would tend to fragment heavily and fell out of favor after the FBI starting touting penetrations as the one and only true god. Technology has not stood still however and most of the fast loading now have benefited by having bullets that are much more likely to hold together and expand to a large diameters. Most that I've looked up expand to about .70" or .80" and penetrate reliably past 12 inches. They are also much less likely to be effected adversely by heavy clothing than the slower loadings. It does come at a price though. The faster loads also kick harder, will produce more muzzle flip, and more muzzle blast. I think most shooters feel the difference in stopping power is not enough to justify the slower shot to shot times. Personally, I really like the faster loads. The faster loads develop anywhere from 500-650 ft/lbs of energy. They expand big, penetrate, and have the capability of doing a lot of damage. I used to shoot the 185+Ps a lot in my 1911 and I never felt the difference in recoil was enough to deter me from these loads. I like them a lot.

rbernie
January 6, 2008, 10:49 AM
Anyone can load a load to higher-than-spec pressure ranges, call it +P and achieve transonic velocities. But my contention remains that the effectiveness of those projectiles is questionable due to their light weight, and you have clearly exceeded the standard pressure ratings for the chambering.

Show me a FBI-protocol terminal ballistics test of any of the loads listed that reliably penetrated past 12" and consistently expanded and that started with a muzzle velocity over 1200fps (a reasonable threshhold value for reliably supersonic, given the fact that each load listed will have actual shot-to-shot velocity variations). Do that, and I'll accept that bullet technology has improved to the point where my first concern has been made moot. Of course, you still are shooting overpressure rounds, but you're certainly free to do so as long as your pistol will hold out.

As an FYI - in most cases, you want to avoid muzzle velocities in the transonic region because it causes aero loadings on the bullet that can (in some cases) dramatically vary its accuracy. That's more of an issue with rifles than with short-range weapons such as handguns, but it is a consideration. Folk that use their handguns in accuracy-based competition tend to try to stay under 1000fps or over 1250 fps from the muzzle to the target.

mgregg85
January 6, 2008, 10:57 AM
Could try the .45 super if you have a good gun. Get yourself a nice strong recoil spring and have at it.

I belive the .45 super will send a 230 grain JHP at around 1100 FPS and a 185 grain JHP at 1300 FPS.

The speed of sound is around 1,129 FPS on a 70 degree day so the 230 load is close and the 185 load is way over.

I'm just waiting for the hypersonic .45 loads to come out...:)

balita
January 6, 2008, 11:22 AM
I love my Kimbers OOOOOO yes. Out of the box the best.

AirForceShooter
January 6, 2008, 11:25 AM
Aguila 117 gr .
Goes supersonic.
LOUD!!!

AFS

whatbrick
January 6, 2008, 01:27 PM
Show me a FBI-protocol terminal ballistics test of any of the loads listed that reliably penetrated past 12" and consistently expanded and that started with a muzzle velocity over 1200fps (a reasonable threshhold value for reliably supersonic, given the fact that each load listed will have actual shot-to-shot velocity variations). Do that, and I'll accept that bullet technology has improved to the point where my first concern has been made moot. Of course, you still are shooting overpressure rounds, but you're certainly free to do so as long as your pistol will hold out.

Only one I could find that matches the criteria listed in the thread, found in this thread (http://glocktalk.com/forums/showthread.php?t=336612) at GlockTalk as posted by Mike McNett of Double Tap:

All of these tests were done using 10% ballistic gelatin provided by Vyse gelatin using all FBI protocols and 4 layers of denim and two layers of light cotton T-shirt in front of the gelatin.

DoubleTap .45ACP
185gr Gold Dot JHP @ 1225fps - 12.75" / .82"
200gr Gold Dot JHP @ 1125fps - 14.25" / .88"
230gr Gold Dot JHP @ 1010fps - 15.25" / .95"

He usually tests all of his .45ACP loads out of a 5" 1911.

jon_in_wv
January 6, 2008, 02:32 PM
Since when is 165-185 too light to work when it is heavier than all 9mm loads and most .40 loads? Are they too light to work too? The lighter loads seem to meet FBIs criteria. The argument they are too light to work doesn't hold water. +P 45 loads don't even approach the 40,000 psi that the .40 operates at. Are the laws of physics different for .45s than they are for 9mm/40/357s??

Guitargod1985
January 6, 2008, 02:42 PM
You cannot get a 45ACP round to be reliably supersonic without making the bullet so light as to be unusable, given the pressure limitations of the chambering.

If it could be done, it would have been.

MagSafe's Super SWAT .45 ACP round is rated at 2260 fps with a 68 grain prefragmented bullet for a total of 771 ft lbs.

http://www.magsafeonline.com/prices_specs.jsp

Yeah, that's a pretty light bullet, but not too much lighter than a standard .380 ACP, which travels a third of this speed. I sure wouldn't want to be in the way of this thing. One of my local gun shops has some ballistic gelatin on which this round was tested. Nasty stuff.

sammoh
January 6, 2008, 02:50 PM
A 65gr bullet out of a .45acp???? Blasphemy!

I've got no problem with the lighter loads but man, a 68 grain bullet? No way. I'll stick with the old tried and true.

BlindJustice
January 6, 2008, 02:59 PM
The speed of sound at sea level with 50% humidity
is approx. 1,130 FPS

Corbon with the conventional JHPs
.45 +P
185 gr. JHP @ 1,150 FPS
or
165 gr. JHP @ 1,250 FPS

I have a load I fire a lot, it's
Leadhead 200 gr. SWC @ ,1,025 FPS
and live at 2,500 elev.

Doing a bit of googling one article states...

Sound waves travel through solids, liquids and gasses. Sound waves travel faster through solids and liquids than gases because they're more dense. At sea level, the speed of sound is 1130 feet per second with 50% humidity.

How does temperature have on the speed of sound?
The higher the temperature, the faster sound travels.

How does humidity affect the speed of sound?
H umidity is a measure of the amount of water vapor in the air; the more humid the air is, the faster sound waves travel in it.**

How does the altitude affect the speed of sound?
Sound travels slower with an increased altitude (elevation if you're on solid earth). This is primarily a function of temperature and humidity changes.


SO is my 200 gr. SWC @ 1,025 FPS
breaking the sound barrier?



But for the O.P. one of the "features" of .45 ACP
is that it IS sub-sonic for the most part and for HD
imho, that's best for firing indoors.

I live at 2,500 Gt Elv.

Guitargod1985
January 6, 2008, 03:02 PM
A 65gr bullet out of a .45acp???? Blasphemy!

I've got no problem with the lighter loads but man, a 68 grain bullet? No way. I'll stick with the old tried and true.

LOL. I wasn't saying I'd use it, just letting y'all know that such a creature exists.

-v-
January 6, 2008, 04:31 PM
BlindJustice, nitpick, but speed of sound is lower at higher temperature, and higher at lower temperature. (Density goes down at High T in an open system)

rbernie
January 6, 2008, 06:18 PM
Since when is 165-185 too light to work when it is heavier than all 9mm loads and most .40 loads? Are they too light to work too? The lighter loads seem to meet FBIs criteria. The fast/light 185gr 45ACP +P load doesn't meet the FBI protocol for barrier penetration; only a single example of a 4-denin gel test.

The argument they are too light to work doesn't hold water. +P 45 loads don't even approach the 40,000 psi that the .40 operates at. Are the laws of physics different for .45s than they are for 9mm/40/357s??
The SAAMI spec pressures for 45ACP are about HALF those of 40S&W and 357 Sig and others. That's why the loadings that purport to achieve transonic/supersonic performance out of the 45ACP are all labelled '+P' - they significantly exceed the standard 45ACP pressure ratings.

Anyone can load a load to higher-than-spec pressure ranges, call it +P and achieve transonic velocities. But my contention remains that the effectiveness of those projectiles is questionable due to their light weight, and you have clearly exceeded the standard pressure ratings for the chambering. This is what I said. I didn't say that you couldn't find examples of supersonic/transonic loadings - just that they would not operate within standard SAAMI specs for the 45ACP chambering and would likely not meet the FBI test protocol (bare gel, clothed gel, and barrier penetration).

Look, guys - here's the protocol (http://greent.com/40Page/general/fbitest.htm). Read it. Find a supersonic load that meets it.

You won't.

The FBI protocol emphasizes penetration over expansion. This was a result of analyzing the 1986 Miami shootout.

http://www.firearmstactical.com/briefs7.htm

Specifically:

As Platt crawled through the passenger side window, one of Dove’s 9mm bullets hit his right upper arm, just above the inside crook of the elbow. According to Dr. Anderson, the bullet passed under the bone, through the deltoid, triceps and teres major muscles, and severed the brachial arteries and veins. The bullet exited the inner side of his upper arm near the armpit, penetrated his chest between the fifth and sixth ribs, and passed almost completely through the right lung before stopping. The bullet came to a rest about an inch short of penetrating the wall of the heart.

After sustaining this wound, Platt continued to fire for several minutes and scored significant hits on FBI agents.

Penetration is key, and a fast/expanding bullet failed to penetrate to the heart due to hitting Platt's arm first.

You may discount the FBI's conclusions. You may decide that they don't apply to you. But you cannot find a supersonic/transonic 45ACP loading that will meet/exceed the FBI tests.

You certainly won't find any that exist within the standard SAAMI pressure specs for the 45ACP chambering.

And that's what I've been trying to say.

Crimp
January 6, 2008, 06:19 PM
Are the laws of physics different for .45s than they are for 9mm/40/357s?? ~jon in wv

In a way, yes! The 45 ACP isn't designed for the pressures of the other mentioned rounds.

Saami specs maximum chamber pressures as:

9mm 35,000 PSI
9mm +P 38,500
40 35,000
357 35,000
45 21,000
45 +P 23,000

BlindJustice
January 6, 2008, 07:22 PM
-v- 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>

I was a Sonar Tech. in the navy - every 4 hours we'd take a
reading on the temp. gradient in the ocean to predict
our ranges for detecting subs. SPeed of sound in salt
water is 4,400 FPS or thereabouts if I recall correctly. Temp.
has more effect, surface and isothermals below the surface
on speed of sound.

If I want to break the speed of sound with my 1911 I will
put the .400 CorBon barrel in it, and replace the stock
recoil spring with a 20 pounder. How about a
155 gr. Hornady XTPJHP @ 1,360 FPS It may go down
to trans-sonic by 100 yards eh?


FWIW - it is estimated Peter Pi's .400 COrBon is loaded
at approx. 26,500 - with the lighter bullet and heavier
recoil spring and a steel frame & slide I don't think the
1911 design is being stressed that much with .400 CorBon.

jon_in_wv
January 6, 2008, 07:28 PM
ok. But that doesn't change the laws of physics. It was stated that there is some strange aerodynamic effect on a 185 grain bullet out of a 45 that would make it inaccurate. Strangely though a 180 grain bullet at even faster speeds is plenty accurate out of a 44 magnum? Also, the question never was whether or not the loads would meet the FBIs protocol. Several of the loads mentioned expand reliably and penetrate reliably past 12-14 inches. Thats working well in my book. The argument could also be made that the slower rounds don't have enough velocity, especially out of shorter barrels, to expand reliably. You also ignored the question of why 185 grains is a "light" bullet when its a heavy bullet in a gun with a .05" smaller diameter and its too heavy to even load in 9mm? I think too many people were soured by the performance of earlier loads like the earlier corbons which fragmented heavily and the Remington 185gr +p that didn't seem to expand reliably. Current loads, especially with modern Gold Dot, Golden Saber, XTPs, or Barnes X bullets seem to perform really well. IF the FBI says they don't isn't really tops on my list of deciding factors. I've read their reports. They have never stated that a large diameter bullet penetrating 12-14 inches is going to be less effective than a smaller diameter bullet penetrating 14-16.

http://www.firearmstactical.com/ammo_data/45acp.htm

Here is a link with results from some testing with the lighter loads. I don't see that they performed poorly at all. Some were not that great but some performed quite well. As well or better than the heavy loads.

CWL
January 6, 2008, 08:56 PM
I don't think the .45ACp was meant to be a 'fast' bullet. It's performed fine as a 236gr. travelling at ~900fps for ~100years now.

If you want big bore & high-speed, consider the 10mm.

BlindJustice
January 6, 2008, 09:29 PM
I think the lower weight 165 gr. - 185 gr. bullets
have the problem of dropping weight and in relation to
the heavier bullets in .45 lose velocity due to their
1 - less weight/momentum/ and 2) fat yes, but in
\relation to their length it becomes a low Ballistic
coefficient.

IMO - the lightest weight in .45 for me is 200 gr.
they can be driven to 1,000 or so and it's not stressing
the gun, good momentum, foot lbs energy and more
reliably expanding compared to 230 gr. plus.

bluetopper
January 6, 2008, 10:24 PM
If the 45 isn't big and fast enough for you, just get a bigger caliber........simple.

Get a 454 Casull or 480 Ruger caliber.;)

rbernie
January 6, 2008, 11:20 PM
It was stated that there is some strange aerodynamic effect on a 185 grain bullet out of a 45 that would make it inaccurate. The transonic region (.8-1.2 Mach) introduces unpredictable buffeting onto the object in flight. Bullets are no exception.

Strangely though a 180 grain bullet at even faster speeds is plenty accurate out of a 44 magnum?Strangely, the 44 Magnum burns a lot more powder under far greater pressures than the 45ACP to drive its bullet at speeds well in excess of Mach 1.2, and therefore avoids the transsonic effects within normal handgun shootin' ranges.

Also, the question never was whether or not the loads would meet the FBIs protocol. Several of the loads mentioned expand reliably and penetrate reliably past 12-14 inches. Thats working well in my book.And that's terrific. You are happy, and that's cool. But your arguing with my assertation that said: ...my contention remains that the effectiveness of those projectiles is questionable due to their light weight, and you have clearly exceeded the standard pressure ratings for the chambering.
All of the huffing and puffing since then has done absolutely NOTHING to demonstrate my point to be invalid. Your reference loads clearly and significantly exceed the SAAMI standards. Your reference loads are, as best I can tell, also not capable of meeting the FBI testing protocol standard, which (like it or not) is a perfectly valid and accepted test regimen for evaluating the terminal performance of a bullet.

You may choose to substitute a differing performance standard; that's OK. But you cannot discount the FBI test protocol as an irrelevant or inappropriate yeardstick. I chose the word 'questionable' in my original posts with care, to allow for the fact that there are differing opinions with regard to what constitutes acceptable terminal performance.

But if you haven't at least QUESTIONED your opinion, and read through the test protocol to determine how relevant you think it might be - then this discussion has been a waste of time.

Here's to hopin' that neither of us are ever forced to find out how correct (or not) our opinions are. :)

also ignored the question of why 185 grains is a "light" bullet when its a heavy bullet in a gun with a .05" smaller diameter and its too heavy to even load in 9mmI didn't ignore it - I didn't realize it was a question. The concept is called Sectional Density (SD), and it's one of the primary factors in determining bullet penetration.

A Google search, or Wikipedia, should give you all the info you need on Sectional Density and how it relates to things.

MachIVshooter
January 7, 2008, 02:57 AM
Does anyone know of some good jhp. rds. for a .45 that are supersonic? I figure if you took a big .45 bullet and made it supersonic it would be one of the most excellent defensive rounds.

Plenty of them. .45 Super, .451 detonics, .460 Rowland, .45 Win Mag., 454 Casull, .460 XVR...................

For a hard-hitting defensive handgun, I prefer 10mm. Easily supersonic with 180 and 200 grain pills from a 3.5" tube. My defensive load is a 180 grain Golden Sabre that clocks 1340 FPS from my Witness Compact.

Double Naught Spy
January 7, 2008, 09:25 AM
After sustaining this wound, Platt continued to fire for several minutes and scored significant hits on FBI agents.

Penetration is key, and a fast/expanding bullet failed to penetrate to the heart due to hitting Platt's arm first.

I love this example. Yes, the 9mm round failed to penetrate to Platt's heart, but it was not because it failed to penetrate the designed amount. The problem was that it first penetrated about 4-5" of soft tissue of Platt's upper arm, in one side, out the other, where it then started to tumble before entering the chest cavity and traveling deep enough to penetrate a lung and nick the aorta.

As it turns out, the round performed to specs, and to the new specs that came AFTER the incident. Most folks consider that the 9mm round failed to penetrate sufficiently as being a problem with the 9mm round and it was not.

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.

jeepmor
January 7, 2008, 10:14 AM
I figure if you took a big .45 bullet and made it supersonic it would be one of the most excellent defensive rounds.

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

ryan in maine
January 7, 2008, 05:37 PM
CWL beat me to it. I was going to say if you want a supersonic .45ACP then take a careful look at 10mm.

*Shrug*

rbernie
January 7, 2008, 06:45 PM
Most folks consider that the 9mm round failed to penetrate sufficiently as being a problem with the 9mm round and it was not.
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. 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.

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.

-v-
January 7, 2008, 11:13 PM
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 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 :p.

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

jon_in_wv
January 8, 2008, 03:17 AM
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"

mastermoparman
January 8, 2008, 06:14 AM
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

markk
January 8, 2008, 06:50 AM
Federal Hydra-Shok 185 gr. +p are rated at 1180...

jon_in_wv
January 8, 2008, 07:30 PM
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.

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