When shooting a handgun, it’s not uncommon to hear a loud blast, but you may be wondering, “Why is the 9mm so loud?” A quick answer is that the bullet is ejected at a higher pressure than other calibers. This is achieved by releasing high-pressure air behind the bullet as it leaves the muzzle.
High-pressure air is released behind the bullet
The bullet’s trajectory affects the air pressure behind it. The amount of air behind a 9mm bullet will vary based on its trajectory and energy. Usually, the bullet’s energy will be proportional to its frontal area. However, if the bullet’s frontal area is small, the air pressure will be relatively high. The pressure wave will propagate outward and will decrease in magnitude as the bullet moves away from the source.
Bullets are typically metal, though they can also be made from plastic and rubber. Lead is the most common material in bullet cores. Because lead is very dense, it can be moulded to create a gas-tight seal inside the barrel, although it is easily deformed upon impact. Lead is also often mixed with other materials such as tin, copper, and antimony.
The pressure inside the cartridge exceeds the amount of friction holding the bullet in place. The bullet is forced to move as the powder burns, and the resulting explosion releases some of the powder out of the muzzle along with the bullet. This causes muzzle flash, which can impair vision temporarily. As a result, manufacturers have developed smokeless powder, which burns much faster and has less muzzle flash.
The 9mm Parabellum (m/39) was first introduced in the Swedish army as an import from Austria. In the early 1960s, the UN-contingent complained about the cartridge’s performance, and the Swedish Army developed a new cartridge for the Carl Gustav m/45. This cartridge had a tombac-plated steel jacket surrounding the lead core. The new m/39B cartridge entered service in the Swedish Army in 1962.
9mm bullets are marked with a unique color, either red or blue. In the United States Military, this is known as a “Special Effects Small Arms Marking System” or SESAMS, and is typically used for training simulations. These are fired from specially modified pistols or rifles.
The bullet’s trajectory depends on several factors, including the initial velocity. The higher the initial velocity, the less the bullet’s flight will be influenced by air. The shape of the bullet also determines its flight characteristics. There are numerous factors that can cause the bullet to follow an abnormal trajectory.
The air behind the 9mm bullet is a mixture of gas and air, but the pressure of the gas is not pre-pressurised. The air is released behind the 9mm bullet by a compressed spring. In addition, the spring is held along with the piston until the trigger is pulled.
When the bullet hits its target, a cavity forms. This cavity expands slightly after impact, but it collapses within a second. This cavity causes trauma to tissue. In addition, the shockwave can damage less-flexible parts of the body or dense organs.
The 9mm round was standardized by NATO. It was produced from December 1941 until 1944. It was intended to be used in semiautomatic pistols such as the Inglis Browning Hi-Power. It is distinguished by a purple-colored ring around the gold-standard primer.