Higher energy .45 ACP. Is there a strategy?

[rpenmanparker]

I don’t do any loading. Just asking those that do, because who would know better?

I learned a couple of weeks ago that .357 Mag can be loaded so hot without having a really high pressure limit because all the space in the oversized case moderates the developed pressure. And of course the 9mm bullet is light enough that it accelerates really fast and relieves the developed pressure by increasing the free space behind it.

Based on that I was wondering if there was a really energetic powder that would produce more thrust per volume used. The idea would be to leave some free space in the cartridge to moderate the pressure even in a hot load. And by moving to a lighter bullet, say 200 gr (roughly corresponding to a 124 gr 9mm bullet) you could both save more space and also get that sucker moving fast, fast. Hopefully in such a situation you could stay at or below the .45 ACP +P pressure limit and have a really high energy round.

Is that how today’s most energetic .45 ACP’s are done? If not, why? No such powder? How far can this be actually pushed with what is available?

 

[6.8KT]

I don't know, but I found this instructive:

https://en.wikipedia.org/wiki/.45_Super
The .45 Super is a powerful smokeless powder center fire metallic firearm cartridge developed in 1988 by Dean Grennell, a well-known writer in the firearms field as well as managing editor of Gun World magazine.[2][3] It is dimensionally similar to the .45 ACP round but has a thicker case wall and is loaded to higher pressures, which offers an average 300 feet per second (91 m/s) improvement in muzzle velocity over the .45 ACP.[4] The cartridge was co-developed by Tom Fergerson and Ace Hindman.

In 1988, a Gun World article detailed Grennell's efforts to update the .45 ACP for the 21st Century, a difficult endeavor due to the inherent design limitations of the veteran round...

 

[Whiterook808]

I can't answer your powder question, but all cartridges have a pressure limit. If SAAMI pressure limits are exceeded your firearm, which most certainly does also have a pressure limit, could fail.

 

[6.8KT]

Also this: https://en.wikipedia.org/wiki/.45_GAP ... It addresses your question to some extent.

 

[rpenmanparker]

I can't answer your powder question, but all cartridges have a pressure limit. If SAAMI pressure limits are exceeded your firearm, which most certainly does also have a pressure limit, could fail.

Right, but I am talking about keeping the pressure down below the limit by making some room in the case by using a lower volume of higher yield powder and reducing the length of the bullet.

 

[rpenmanparker]

Also this: https://en.wikipedia.org/wiki/.45_GAP ... It addresses your question to some extent.

Yes, the general topic is addressed, but rather in reverse of what I was trying to accomplish. It appears the .45 GAP is a handicapped .45 whereas I was pointing toward a hot one. The idea of getting more out of less powder resonates, but in the GAP case that is needed to overcome the shortening of the casing, whereas I was proposing to do it to provide more empty space in the cartridge.

 

[40-82]

Medium burning powders will usually give you a slight increase in velocity in the 45 ACP for the same degree of pressure. Lighter bullets, 185 or 200 grain, loaded at top end will also give you more velocity than an equal pressure load from the standard 230 grain load. The lighter, faster loads will also deliver more foot-pounds of energy.

Foot-pounds of energy, though, may not be a reliable indicator of killing power at least in small increments. In large increments of course it is. A .460 Weatherby has more foot-pounds of energy than a . 22 magnum, and it kills better. Many swear by the lighter, faster .45 ACP loads. Others swear at them. I have no doubt that a lightweight .45 ACP bullet loaded to maximum velocity with hollow points would dramatically perform better on a gelatin block. On flesh and blood it might not make as much difference.

In today's world you run into more and more variations in bullet type and design along with slight improvements in velocity and fewer and fewer people with the perspective of having shot hundreds of things in the field with those cartridges, which often translates into the most dramatic assertations of performance being based on little real experience.

I'm as guilty as the next of limited experience. The last time I checked prices many of the various .45 ACP hollow point bullets sold for fifty cents a piece just for the bullet alone, not the loaded cartridge. I'm in no financial position to pay fifty cents plus primer and powder and a case I'm liable to lose ever time I see something I want to eat and the only gun I have close is a .45 ACP. I use an RCBS copy of the old Lyman 452377 roundnose that comes in usually at about 228 grains. Put it in the right place and it does well. Screw up and it doesn't. The same can be said for a .22 short, but the .45 does give a bit more margin of error.

As for powders, I worry more about accuracy than velocity. I'm not convinced fifty feet per second one way or the other is going to make that much difference in a cartridge like the .45 ACP, but even if you do I'd add this caveat: maximum pressures wear your gun and your cases harder, and the last thing you want is a failure when you really need the thing to go bang.

 

[Charlie98]

Not to rain on your parade, but if there was the ability to load something like that... the ammo companies would be doing it. Hornady has sort of done it in some rifle cartridges with their 'Superformance' line. I bought a box of it for my M1a... I think I fired 2 rounds through it before I decided maybe that wasn't the hot setup for the M1a action. Energy is energy... you have to pay the bill for it somewhere along the line...

 

[fxvr5]

Gunpowder selection is very important, and there can be some powders that will produce higher than usual velocities and stay within standard pressure limits.

However, the idea of "making/leaving room in the case" does not apply here, because it is not relevant. That is, how much free space is available in the case after you load the powder and bullet does not matter. So toss that idea out the window. You've over-generalized from the 357 magnum stuff. It simply is not an issue.

All that matters is that a given powder, because of its burn rate properties and its specific performance in a specific cartridge, will push bullets a bit faster than other powders at the same pressure. It's that simple. You don't need to consider the available space in the case after the powder and bullet are loaded.

Are there 'magic' gunpowders that provide super-duper performance compared to other powders in the cartridge? Well, Power Pro 300-MP seems to produce some pretty fast loads in the 357 Magnum, according to the Hornady load manual for some bullet weights. It will beat other powders, even like the favorite 296, by 100-150 fps, which is quite a bit by any standard. In the 45 Auto, Ramshot Enforcer can reach near +P velocities and still stay within standard pressure limits. But Enforcer fills the case. In the 38 Super, one of the better powders for performance is N105, producing some of the highest velocities with 124 grain bullets (1450 fps), and it is compressed.

So, there are some powders that can produce very high speeds and keep pressure low. But 'left over space in the case' is irrelevant.

Enforcer in the 45 Auto: https://www.shootingtimes.com/editorial/fast-loads-for-the-45-acp/99214
N105 in the 38 Super: http://www.shootingtimes.com/editorial/super-powders-for-the-38-super/99160

Oh, one more thing. "And of course the 9mm bullet is light enough that it accelerates really fast and relieves the developed pressure by increasing the free space behind it." This applies to every cartridge and bullet, not just the 9mm. As a bullet moves forward, the available space increases. Period. No matter the cartridge or bullet. So toss this idea out the window, too.

 

[6.8KT]

Yes, the general topic is addressed, but rather in reverse of what I was trying to accomplish. It appears the .45 GAP is a handicapped .45 whereas I was pointing toward a hot one. The idea of getting more out of less powder resonates, but in the GAP case that is needed to overcome the shortening of the casing, whereas I was proposing to do it to provide more empty space in the cartridge.

Right. The GAP shaves 3mm off the case and use 'hotter' powder resulting in +P+ pressures and necessitating a stronger case to achieve the same performance as ACP.
The Super uses a case the same size, with hotter powder [and probably more of it] resulting in the same as above -- higher pressure, stronger case .. but achieves +300fps.

So, as someone who absolutely does not know what he's talking about, my guess is that you could use a shorter bullet, less but hotter powder, up to +P pressures without needing a stronger case... and probably get 1,300fps like the Underwood .45ACP 185gr +P.

 

[Texas10mm]

The .357 Mag has a SAAMI pressure limit of 35k. The .45 ACP has a pressure SAAMI pressure limit of 21k.

The .45 ACP has slightly more case capacity than the .357 Mag.

It's not quite as simple as you make it out to be.

 

[RecoilRob]

Velocity is limited by maximum pressure and, more importantly, the time/pressure curve being that the same pressure applied over a longer time period imparts more energy to the projectile. So small amounts of a fast high energy powder can and will hit the pressure limit, but the curve will be much like a sharp spike. Conversely a larger charge of slower burning powder which achieves the exact same max pressure most often will develop more velocity because the curve is more broad with pressure coming up and going back down less rapidly. The answer to more velocity is more powder while still observing the max pressure limits.

There are cases where a smaller amount of faster powder can offer superior performance, but these are rare and limited to very short barrels where the extra pressure curve is wasted out of the muzzle. With normal (even short) barrel lengths most often the powder that delivers the highest velocity from a long barrel will also be fastest in the short tube.

 

[Dibbs]

Bear in mind the 1911 was designed around the 45ACP. It's a rimless cartridge, designed
specifically to be shout thru mags in autoloaders. Part of the whole point of the 45ACP is
a fat, slow (and relatively lower power ) round, designed with a specific performance criteria
in mind.

Now, the 44 Remington Magnum, approximately the same size bullet, uses @ 3 to 4 times the powder
of a 45ACP, is a rimmed cartridge, of substantially longer length, and has considerably increased
ballistic performance.

Even if you were to increase the performance of a 45ACP round, there's a good chance you would
exceed safe tolerance level parameters of the chambers of the pistols firing it.

 

[CMV]

This is how much powder is in a .45ACP round. Empty case, 230 gr FMJ bullet, 115gr 9mm bullet for reference. As you can see a very tiny amount with lots of free space left in the case. Not like say .308 WIN where the bullet has to "squish" down the powder in the case to seat because there is so much.


Interesting (maybe) to you, but I load a .45ACP with a 230 gr bullet with exact same powder and amount as I do 9mm with a 115gr bullet....I'd have never guessed that to be the case before I got into reloading.

 

[bersaguy]

Not much left to be gained from increased case capacity in 45auto...or any caliber for that matter. You could do the same thought experiment for any cartridge, denser...maybe slower powder, to increase velocity while keeping pressure in line. There are marginal gains to be had staying within the same case. Comparing 357mag to 9mm, where you have 357 pushing a heavier bullet to a higher velocity than 9mm at similar pressures...you have to remember, 357 has twice the case capacity of 9mm. So an increase of 10% 15% or even 20% will not get near the capacity difference of 357vs9mm. Titegroup is the densest powder I load in 45, about 4.7 grains. And that fills the case about 1/3rdish full. Let's say some superduper powder formula can get me the same energy with half the powder, so I load 2.3 grains or 1/6th full...I'm still not picking up much more empty space in the case.

 

[Rule3]

I don’t do any loading. Just asking those that do, because who would know better?

I learned a couple of weeks ago that .357 Mag can be loaded so hot without having a really high pressure limit because all the space in the oversized case moderates the developed pressure. And of course the 9mm bullet is light enough that it accelerates really fast and relieves the developed pressure by increasing the free space behind it.

Based on that I was wondering if there was a really energetic powder that would produce more thrust per volume used. The idea would be to leave some free space in the cartridge to moderate the pressure even in a hot load. And by moving to a lighter bullet, say 200 gr (roughly corresponding to a 124 gr 9mm bullet) you could both save more space and also get that sucker moving fast, fast. Hopefully in such a situation you could stay at or below the .45 ACP +P pressure limit and have a really high energy round.

Is that how today’s most energetic .45 ACP’s are done? If not, why? No such powder? How far can this be actually pushed with what is available?

Load (or buy) a 185 gr bullet, use slow powders, load to +P levels and that's about as far as the "envelope" can be pushed.

Buffalo Bore is their claim to fame so to speak.

https://www.buffalobore.com/index.php?l=product_list&c=12

 

[6.8KT]

This is how much powder is in a .45ACP round. Empty case, 230 gr FMJ bullet, 115gr 9mm bullet for reference. As you can see a very tiny amount with lots of free space left in the case. Not like say .308 WIN where the bullet has to "squish" down the powder in the case to seat because there is so much.
View attachment 822560

That's not a lot of powder.
How much does the powder charge vary in terms of volume from least to greatest? And what's the determining factor as to how much is used? Is it the "burn rate" or "specific energy" or something else?

 

[jmr40]

The 45 Super can be fired in many 45 ACP pistols with some modifications to the gun. This is the best way to achieve your goals.

https://en.wikipedia.org/wiki/.45_Super

Energy never killed anything. Shot placement and bullet penetration do. If you increase velocity at the expense of accuracy or penetration you haven't gained anything.

Going to a lighter bullet means you can use more powder and increase muzzle velocity. But that doesn't mean better performance at impact. If you can find a way to get a little more speed with standard weight bullets it can help some. Lighter bullets in the same caliber are short and fat. Short, fat bullets may leave the muzzle faster, but they also slow down faster as soon as they leave the barrel. They also don't penetrate nearly as well after they impact. Bullets that are longer tend to perform better after they leave the muzzle even though they may be slower.

 

[Walkalong]

The .357 Mag has a SAAMI pressure limit of 35k. The .45 ACP has a pressure SAAMI pressure limit of 21k.

The .45 ACP has slightly more case capacity than the .357 Mag.

It's not quite as simple as you make it out to be.

This.

And we don't do hot rodding calibers.