A pistol can be described as a handgun with a chamber integral to its barrel.
There are various types of pistols worldwide, such as semi-automatic, fully automatic, single-shot, manual repeating, etc.
Pistols were found in the 16th century in Europe. Two such pistols are 45 ACP and 45 GAP.
Key Takeaways
- The .45 ACP has been used for over a century, is more widely available, and has more ammunition options than the newer .45 GAP.
- The .45 GAP is a more compact cartridge and allows for a smaller grip size on pistols, making it more suitable for concealed carry.
- The .45 ACP generally has higher muzzle energy and greater stopping power than the .45 GAP.
45 ACP vs. 45 GAP Pistols
45 ACP cartridges are available and come in various loads, making them suitable for everything from self-defense to target shooting.45 GAP (Glock Automatic Pistol) is a recent cartridge designed for Glock pistols. It has a shorter length and a higher pressure than 45 ACP.

45 ACP is a pistol where ACP stands for automatic Colt pistol. It originated in n the year 1904 by John Moses Browning.
It has a 230-grain bullet weight and is quite popular among large-caliber sports shooters and the army. It provides excellent accuracy and power when used against human targets and operates at 21.000 psi chamber pressure.
The diameter and length of 45 ACP are quite significant.
45 GAP is a pistol where GAP stands for Glock auto pistol and is designed by Ernest Durham. It is also known as the 45 Glock. It has a slightly short diameter and length.
It has a maximum bullet weight of 200 grains and is operated at a pressure of 23,000 psi. Its total length is 27.22 mm.
Four state law enforcement agencies have accepted the 45 GAP as a replacement for the service gun, thus making it a very popular pistol among other manufacturers,
Comparison Table
Parameters of comparison | 45 ACP | 45 GAP |
---|---|---|
Definition | It is a pistol | It is a pistol but is slightly shorter than 45 ACP. |
Full form | ACP stands for Automatic Colt pistol. | GAP stands for Glock auto pistol |
Operating pressure | It operates at a pressure of 21,000 psi | It operates at a pressure of 23,000 psi |
Bullet weight | 230 grains | 200 grains |
Origin | John Moses Browning designed it in the year 1904. | It was created in 2003 by Ernest Durham. |
What is 45 ACP?
45 ACP is a pistol where ACP stands for automatic Colt pistol. It is also known as 45 Auto and was designed by John Moses Browning in 1904.
It is a rimless straight-walled handgun cartridge. A standard-issue military 15 ACP round travels 830 feet per second and has a 230-grain bullet weight.
It has continuously ensured its worth and popularity among large-caliber sports shooters and in the army. However, in 1985, the Beretta M9 9mm pistol replaced the 45 ACP M1911A1 pistol used by the US military as their sidearm.
It provides excellent accuracy and power when used against human targets. It has a low blast and flash and operates at 21.000 psi chamber pressure.
45 ACP cartridge is available in various specialty rounds, weights, and performance levels. The diameter and length of 45 ACP are appreciable, which makes its grip better.
However, this might sometimes create a problem for shooters with small hands.
It is known to be one of the most potent pistol calibers used in suppressed weapons. There are some derivative versions of 45 ACP, such as 45 Super and 460 Rowland.
45 Super is almost similar to 45 ACP except for its developer-established pressure of 28,500 psi. At the same time, Rowland has a pressure of 40,000 psi and is commonly used by a selected number of people.

What is 45 GAP?
45 GAP is a pistol where GAP stands for Glock auto pistol. It is also known as the 45 Glock and was designed in 2003 by Ernest Durham.
It is designed to have a strong case head to minimize the possibility of case neck blowouts. It has a small size which makes it easier to handle. It has a slightly shorter diameter than its predecessor and uses a small pistol primer.
The maximum bullet weight of this product is 200 grains. This pistol uses a 45 GAP cartridge, compact Glock 39, and subcompact Glock 39.
45 GAP has been adopted as a replacement for the service gun by four state law enforcement agencies current issue.
It gained popularity among other manufacturers due to its acceptance by law enforcement agencies.
Therefore, many manufacturers made pistols models that can use 45 GAP cartridges. This pistol has a rimless, straight case and an overall length of about 27.22 mm.
It is known to have the developer established pressure of 23,000 psi.

Main Differences Between 45 ACP and 45 GAP
- 45 ACP is a pistol where ACP stands for automatic Colt pistol, whereas 45 GAP is a pistol where GAP stands for Glock auto pistol.
- John Moses Browning designed 45 ACP in the year 1904. in contrast, the 45 GAP was created in 2003 by Ernest Durham.
- 45 ACP has a larger size than 45 GAP.
- Law enforcement agencies accept GAP pistols, whereas such agencies do not accept ACP pistols.
- GAP operates at a higher pressure, i.e., 23,000 psi, than the ACP pistols, i.e., 21,000 psi.
- The maximum bullet weight of a 45 GAP pistol is 200 grains, whereas a 45 ACP pistol has an ultimate bullet weight of 230 grains.

- https://www.ncjrs.gov/App/abstractdb/AbstractDBDetails.aspx?id=235469
- https://www.sciencedirect.com/science/article/pii/S0003497516303988
Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.