.45 ACP Ammo Guide: M1911 History, 230 Grain Ball and +P

.45 ACP is a large-bore pistol cartridge designed by John Moses Browning in 1904 and adopted by the US Army in 1911 along with the Colt M1911 pistol. Its classic military load is a 230 grain round-nose full metal jacket bullet at about 830 feet per second, which is slower than the speed of sound. We do not stock .45 ACP right now. This guide covers the cartridge so you can choose ammunition with confidence, and points to the 9mm Luger we do carry.

Browning, the M1911 and the Army

Browning designed the cartridge in 1904. In 1911 the US Army adopted it as the caliber .45 automatic pistol ball cartridge, model of 1911, for the M1911 pistol. The M1911 and its M1911A1 update served as the standard US military sidearm for decades, which is why the cartridge is tied so closely to the 1911 platform today. ACP stands for Automatic Colt Pistol. The SAAMI standard lists it as 45 Automatic, or 45 Auto.

230 grain ball and other weights

The 230 grain full metal jacket round-nose load, often called hardball or ball, is the reference load for .45 ACP and the one the original pistol was designed around. The SAAMI standard lists bullet weights from 185 to 230 grains for standard .45 Auto. Heavier bullets in this caliber are large and comparatively slow. Defensive loads are typically jacketed hollow points, and many target shooters use lighter semi-wadcutter or match loads, which SAAMI covers under a separate 45 Auto Match listing.

Why .45 ACP is subsonic

Standard-pressure .45 ACP loads leave a handgun below the speed of sound. That means no supersonic crack as the bullet travels, which is why .45 ACP has a long history with suppressed pistols and submachine guns. The low velocity comes from the cartridge's low working pressure. SAAMI sets the maximum average pressure for 45 Auto at 21,000 psi, well under the 35,000 psi limit for 9mm Luger.

.45 ACP +P

As with 9mm, there is a +P version loaded to a higher pressure for more velocity. SAAMI sets 45 Auto +P at 23,000 psi. The same rule applies: use +P only in a pistol its maker rates for it, and check the owner's manual. Some older pistols and some lightweight compacts are not rated for it.

How to choose .45 ACP ammo

• Confirm the chamber. .45 ACP is not the same as .45 GAP, .45 Colt or .450 Bushmaster. Match the box to the barrel marking.
• Check feeding in your 1911. Many 1911s were designed around round-nose ball. Test hollow points through every magazine you carry.
• Know your pressure rating. Standard loads suit any sound .45 ACP pistol. +P needs the maker's approval.
• Store it cool. Phoenix summer heat is hard on powder and primers. Keep ammunition indoors.

What we stock instead

We do not stock .45 ACP. Our handgun line right now is 9mm Luger and 5.7x28mm. If you are comparing calibers for a new pistol, our 9mm ammo guide covers the most common pistol caliber, and our 9mm +P vs standard page explains pressure ratings in more detail. In 9mm we carry Speer Gold Dot LE Duty 147 grain (53619), a heavy, standard-pressure hollow point, and Speer Gold Dot LE Duty 124 grain +P (53617), both in 50 to 1,000-round packs. Browse 9mm Luger or all pistol ammo.

You must be 21 or older to order from us. Orders ship UPS Ground from Phoenix within 2 business days, and Phoenix-area customers can pick up with ID Monday to Friday, 9am to 5pm. Call 480-623-4515 with questions.

.45 ACP questions

Is .45 ACP the same as .45 Auto?

Yes. .45 ACP, .45 Auto and .45 Automatic are names for the same cartridge. .45 GAP and .45 Colt are different cartridges and do not interchange with it.

Is standard .45 ACP ammo subsonic?

Yes. Standard-pressure .45 ACP loads, including 230 grain ball at about 830 feet per second, travel below the speed of sound from a handgun. That is one reason it is popular for suppressed shooting.

What is the pressure difference between .45 ACP and .45 ACP +P?

SAAMI sets the maximum average pressure at 21,000 psi for standard 45 Auto and 23,000 psi for 45 Auto +P. Use +P only where the pistol maker approves it.

Does Heisenberg Ammo carry .45 ACP?

Not right now. We stock 9mm Luger Speer Gold Dot and 5.7x28mm for handguns. See our ammo FAQ or FMJ vs hollow point for general guidance that applies to any caliber.