Compared: The .357 Magnum and .45 ACP
By Chuck Hawks
These are two of the best civilian personal protection handgun cartridges and they have also been adopted by many police departments. In addition, the .45 ACP has been used by various military services and the .357 Magnum is often chosen for protection against both two and four-legged predators in the field, as well as for handgun hunting. Typical bullet weights for the .357 Magnum range from about 110 grains to 200 grains and for the .45 ACP from about 180 to 230 grains. The .357 Magnum is chambered in a wide variety of revolvers of all sizes, while the .45 ACP is available in a variety of large frame autoloading pistols.
Introduced by Smith & Wesson in 1935, the .357 Magnum was the original magnum revolver cartridge. It was based on a lengthened and strengthened .38 Special case loaded to higher pressure. For this reason, any .357 Magnum revolver can also safely fire all .38 Special and .38 Special +P ammunition. The .357 is one of the all-time best selling handgun cartridges, widely used for both hunting and personal defense. It has also been adapted to single shot, pump and lever action rifles.
The .357 Magnum has become the standard of comparison among personal defense handgun cartridges, with the highest percentage of one shot stops of any handgun cartridge. Almost every revolver that can stand the pressure is chambered for the .357 Magnum and there is an equally large selection of factory loaded .357 Magnum ammunition. Virtually all ammunition manufacturers load .357 Magnum cartridges. There are small frame, medium frame and large frame .357 revolvers. It is also one of the most popular calibers in single shot pistols and even autoloading pistols have been adapted to the cartridge, making for an extensive choice of guns in the caliber.
For most of its life, the standard .357 Magnum factory load has driven a 158 grain bullet (lead, JSP or JHP) of .357" diameter at a muzzle velocity (MV) of 1550 fps from an 8-3/8" barrel (Remington figures). Because the .357 was loaded to full pressure, this velocity figure was pretty close and has been verified by independent chronograph tests, including mine. In this, the age of the tort lawyer, the SAAMI maximum average pressure (MAP) of the .357 Magnum has been reduced to 35,000 psi. The factory loaded 158 grain bullet now has a catalog MV of approximately 1250 fps and muzzle energy (ME) of 548 ft. lbs. from a 4" vented test barrel.
According to Marshall and Sanow's definitive stopping power research, the top .357 load (Federal 125 grain JHP) achieves 97% one shot stops in police recorded shootings. The general purpose 158 grain JHP loads from Federal and Remington achieve about 81% one shot stops on human predators and are also quite useful in the field for protection against both two and four legged predators, as well as for handgun hunting. These statistics are based on rounds fired from 4" revolver barrels, as typically used by police agencies. Longer 6" and 8" revolver barrels substantially increase the effectivness of the .357 Magnum cartridge.
.357 Magnum reloaders have a huge choice of suitable bullets and powders. According to the Hornady reloading manual, reloaders can drive 158 grain bullets at up to 1400 fps and 180 grain bullets at 1150 fps from an 8" revolver barrel within current SAAMI pressure limits.
Most .357 revolvers are highly accurate, an advantage over the great majority of autoloading pistols, particularly those using the Browining designed tilt-barrel (short recoil) action typical of 1911 pistols. In terms of reliability, no autoloading pistol is as dependable as a good revolver when the whistle blows.
The famous .45 Automatic Colt Pistol cartridge was designed by John Browning in 1905 for a prototype service pistol. The U.S. Army tested both the pistol and cartridge and requested some changes, including a heavier bullet (the original weight was 200 grains). Browning changed the bullet weight to 230 grains at 850 fps and the .45 ACP as we know it today was born. The Army adopted both the cartridge and the Browning designed Colt pistol in 1911 and both are still going strong today.
The .45's best one shot stop percentage is 94% with the Federal +P 230 grain Hydra-Shok load, which is a very high number. Ball (FMJ) ammo is much less effective, with one shot stopping percentages around 64% (Federal and Winchester loads). Not all pistols will feed all loads and some, including Government issue M-1911 pistols, may not reliably feed anything but 230 grain ball (FMJ) ammo. Modern pistols, such as the Glock and SIG, are designed to function correctly with JHP ammo, but it is wise to shoot any .45 ACP pistol extensively with whatever ammunition is chosen for self-defense to verify its reliability.
Modern .45 ACP factory loads usually come with 185, 200 or 230 grain bullets, in JHP and FMJ styles. Unless you are stuck with a .45 pistol that will feed only ball ammo, use JHP bullets for self-defense. Because 230 grain FMJ ammo is cheaper than JHP ammo, and because the .45 ACP is an expensive caliber to feed under the best circumstances, most users choose a good 230 grain JHP bullet for self-defense and practice mainly with cheaper 230 grain ball ammo. This avoids having to re-zero the pistol after every practice session. Anyway, most .45's have fixed sights, regulated for the 230 grain bullet, and cannot be re-zeroed for other loads.
The typical factory load for the .45 ACP uses a 230 grain bullet (either FMJ or JHP) at a published muzzle velocity (in a 5" barrel) of 850 fps with 370 ft. lbs. of muzzle energy. Because the .45's short, fat, slow bullet falls pretty fast as the range lengthens, outdoorsmen are better off carrying something else in the field, such as a magnum revolver.
In the interest of consistency, we will use standard Hornady Custom factory loads in each caliber for this comparison. These are not maximum pressure loads for either caliber, but they are typical of standard .45 ACP and .357 Mag. factory loads from the major U.S. manufacturers.
To represent the .357 Magnum, we will use the 158 grain factory load. To represent the .45 ACP we will use the 230 grain factory load. We will compare these factory loads in velocity, energy, trajectory, sectional density, bullet diameter and recoil.
Velocity is important for initiating bullet expansion and it is the most important factor in calculating kinetic energy. Higher velocity flattens trajectory, making hitting easier at extended ranges and particularly at unknown ranges in the field. Here are the published velocities in feet per second (fps) of our comparison loads at the muzzle, 50 yards and 100 yards.
The .357 Magnum shows a big advantage in velocity at all ranges, ranging from 400 fps at the muzzle to 285 fps at 100 yards.
Kinetic energy is defined as the ability to do work. In this case, the "work" involved is primarily powering bullet penetration and expansion. Both are, of course, necessary for lethality. It is also worth noting that kinetic energy is also reasonably good indicator of potential killing power. Here are the energy figures in foot-pounds (ft. lbs.) for our comparison loads at the muzzle (ME), 50 yards and 100 yards.
The .357 clearly has a sizeable advantage in energy over the .45 at all ranges. This bodes well for its killing power, at home or in the field.
Velocity and ballistic coefficient (BC) are the factors that primarily determine a bullet's trajectory. Sometimes the need for personal defense occurs at greater distances than anticipated. Seven yards or less may be the statistical average, but sometimes bad guys do not play by the rules and bring slug shooting shotguns, rifles or magnum revolvers to gunfights. In such circumstances, the need to reach out and touch someone makes a flat trajectory important. The flatter the trajectory, the easier it is to hit the target as the range increases. This particularly applies to those who carry a handgun for protection against two-legged and four-legged predators when camping, fishing or hiking. Trajectory is even more important for a hunting handgun and many .357 revolvers are used for hunting.
For purposes of comparison, we will assume a 25 yard zero distance, as Hornady does for their published trajectory figures. Here are the approximate trajectories for our comparison loads from 25 yards to 100 yards.
As you can see from these numbers, the .357 Mag. shoots much flatter than the .45 ACP. This is due to both its higher velocity and the superior BC of its bullet.
Sectional Density is the ratio of a bullet's weight (in pounds) to its diameter squared (in inches). SD is important when comparing cartridges and loads because, other factors (such as impact velocity and bullet expansion) being equal, the bullet with the greatest SD will penetrate deeper, creating a longer wound cavity and increasing tissue destruction. Obviously, however, if the bullet penetrates all the way through the target, wounding ceases. Superior SD also improves the penetration of barrier materials, giving the bullet a better chance to reach a target on the other side (other factors being equal). The actual bullet diameter of the .357 Magnum is .357" and the actual bullet diameter of the .45 ACP is .451"
The .357/158 grain bullet has a clear advantage in SD over the .45/230 grain bullet. This means that the .357 should provide superior penetration with bullets of the same expansion characteristics.
Bullet diameter determines cross-sectional area. Given an equal percentage of bullet expansion, a larger diameter bullet will create a wider wound cavity, destroying more tissue. In terms of wound cavity volume in soft tissue, bullet diameter and SD somewhat tend to balance each other. Bigger diameter creates a wider bullet track and superior SD a longer bullet track, other factors being equal. Here are the actual bullet diameters of our two cartridges.
The .45 has an obvious advantage over the .357 in bullet diameter and cross-sectional area. It should produce a wider wound channel.
Recoil is a bad thing, as it distracts the shooter, leads to flinching, degrades accuracy and increases the recovery time required for subsequent shots. Anyone can shoot better with a pistol that kicks less.
One of the most popular .45 ACP service pistols is the Glock 21, widely chosen by both police and civilians for personal protection. The G21 weighs around 2.4 pounds with a loaded magazine. It is hard to say what is the most popular, full size .357 revolver, but the Ruger Blackhawk with a 6.5" barrel must be right up there. The Blackhawk weighs about 3.0 pounds. These are the gun weights we will use when calculating the recoil of our comparison loads.
The .357 generates more recoil energy than the .45 in our test guns, while the .45 has a higher recoil velocity than the .357. However, in guns of identical weight the .357 would kick harder than the .45.
Both cartridges generate considerably more recoil than guns of similar weight shooting .38 Special or 9x19mm cartridges. .45 ACP pistols can ONLY shoot .45 ACP ammunition, but all .357 revolvers can also shoot .38 Special cartridges. This gives the .357 a big advantage in reduced recoil for target shooting and practice sessions. In addition, many .357 owners use .38 +P loads for home defense or personal protection, to take advantage of the lower power cartridge's reduced recoil, flash and muzzle blast.
Summary and Conclusion
The .357 Magnum beats the .45 in every performance category except bullet diameter. A .357 Magnum revolver is also more versatile than any .45 ACP pistol, because it can handle a wider range of bullet weights and loads, including all .38 Special ammunition. .38 Special factory loads are much less expensive than .357 Magnum or .45 ACP ammo, substantially reducing the cost of practice sessions.
Both cartridges are excellent for self-defense in urban or suburban settings. In addition, the versatile .357 is a viable choice for handgun hunting and general field use, applications for which the .45 ACP is poorly suited. The .357 Magnum is also popular for use in lever action rifles, where it serves nicely as a short range (100 yard) hunting and plinking cartridge. By any rational standard, the .357 Magnum is the superior cartridge.
Copyright 2013 by Chuck Hawks. All rights reserved.