Forgot to mention, .45 caliber means the bullet is 5 thousands of an inch smaller than a half inch. If you have calipers or a mic, measure the bullet to make sure what you have, it would measure .451 or .452, and weigh 230 grains if it's the military version, which it probably is from what I can see just looking at the picture. The cartridge was invented by John Browning in 1904 for his semi auto pistol, which was adopted by the army in 1911 as their service pistol, and which is the reason it's called a model 1911. That pistol stayed in service until 1985, when it was replaced by the 9mm, but recently the .45 cartridge is making a comeback, especially by the special forces, but not the 1911 pistol, they are using a more modern firearm.