Family
Cookbook
Travel
Guns
Teach
Cartridges
Shooting Skills
Maintenance
General Information
Links
.45 Automatic Colt Pistol - ACP
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 ACP case has a very slight taper from rim to case mouth of
.007 inch. This is about half the taper of the 9mm Luger case and
probably not enough to significantly enhance the feed reliability
of a cartridge as fat as the .45.
The .45 ACP cartridge remained service standard with the U.S. Army
until 1985, when it was replaced by the NATO standard 9x19 (9mm
Luger). This set the record for longevity and it may never be
broken. The .45 ACP served the U.S. well in WW I, WW II, Korea,
and Vietnam. In the 1950's it became the favorite cartridge for
the new sport of combat pistol shooting, so much so that the
USPSA/IPSC rules were rigged in its favor.
The .45 has become so legendary in the U.S. that it is difficult
to write about it honestly without offending some readers. It is
an excellent cartridge for self-defense, but not the absolute
best. The Colt 1911 Government Model is a fine pistol, but there
are simpler, more reliable, higher capacity designs available in
.45 ACP (as well as other cartridges). The .45 ACP did not provide
the stopping power that saved U.S. servicemen from knife wielding
natives in the Philippines in the early years of the 20th Century,
that was the .45 (Long) Colt cartridge and the old Colt SAA
(Peacemaker) revolver.
The original and still common 230 grain FMJ .45 bullet is not a
90% stopper, as was once widely asserted. Its actual one shot stop
percentage is about 63% and that number is not significantly
better than the percentage for the equivalent 124 grain 9mm FMJ
bullet (about 62%). These are the facts, as Joe Friday used to say
on the old TV series Dragnet, only the facts.
None of this is intended to belittle the .45 ACP, which is one of
our best self-defense cartridges. Its best one shot stop
percentage is 94% with Federal 230 grain Hydra-Shok bullets, which
is a very high number. Other good .45 ACP loads are the Cor-Bon
185 grain JHP at 92%, CCI 200 grain JHP at 88%, Federal 185 grain
JHP at 87% and Remington +P 185 grain JHP at 86%. Not all pistols
will feed all loads and some, including Government Issue M-1911
pistols, may not feed anything but 230 grain ball (FMJ) ammo
reliably. Modern pistols like the Glock and SIG are usually
reliable with all modern 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 nothing else, use the ball ammo for
practice and stick to 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, many
fans 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 .45s have fixed sights, regulated for the 230 grain bullet.
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. This load
has a mid-range trajectory of .4" over 25 yards, 1.6" over 50
yards and 3.7" over 75 yards. Beyond that the fat, slow bullet is
falling pretty fast, but not many people can hit reliably at long
range with a .45 auto, anyway. The outdoorsman would be better off
carrying something else.
As one would expect, there are plenty of reloading components for
the .45 ACP. The Speer Reloading Manual Number 14 shows that their
230 grain Gold Dot HP bullet can be driven at a MV of 702 fps by
7.2 grains of HS-6 powder, and a MV of 799 fps by 8.0 grains of
HS-6. These loads used Speer cases and CCI 300 primers and were
tested in the 4.4" barrel of a SIG P220 pistol.
The .45 ACP has a reputation as being a hard kicking cartridge,
difficult to shoot well. To an extent it is, because it throws a
heavy bullet. If you make a .45 auto light enough for comfortable
concealed carry, it kicks pretty hard. A gun heavy enough to
dampen some of the recoil, like a Colt Gold Cup target pistol, is
considered too heavy and bulky for daily concealed carry by most
civilians. Some of the felt recoil may also be attributable to the
ergonomics of the Colt Government Model pistol, which definitely
does not fit every hand. (The Glock 21, for example, with its more
relaxed grip angle has a reputation as a "soft" shooting .45).
People with small hands are liable to have trouble controlling any
large frame auto pistol. This is one reason the .45 ACP has never
been particularly popular as a police service cartridge, although
modern .45 Autos, such as the Glock and SIG-Sauer, have made some
inroads in the police market.
Another reason for the Colt 1911 / .45 ACP's limited popularity
with police agencies is the fact that the Colt auto is a single
action pistol that must be carried "cocked and locked" (chamber
loaded and hammer on full cock, manual safety engaged) if it is to
be gotten into action quickly from a holster. Cocked and locked
carry gives many people the willies, including liability conscious
police commissions. Modern pistols, like the double action SIG or
"safe action" Glock, do not have this problem.
At least part of the reason for the .45's reputation for mediocre
accuracy is due to the fact that John Browning's historic M1911
service pistol was designed to work under combat conditions and
the tolerances are pretty loose. Nor was Government Issue .45
hardball ammunition loaded to the most stringent standards of
accuracy. A standard GI .45 shooting hardball ammo is simply not a
particularly accurate pistol, no matter how cool and experienced
the shooter. However, a target grade .45, shooting target grade
ammunition, is capable of shooting fine groups at 25 yards.
The .45 ACP is a fine old cartridge, not as good as its most
ardent admirers believe, nor as bad as its most negative critics
imply. The .45 Auto may not the best choice for many purposes, but
it is in the upper echelon of combat pistol cartridges.