Heckler & Koch MP5/40 and MP5/10
The MP5/40 and MP5/10 are product improved variants of the 9mm MP5 chambered for the more powerful .40 S&W and 10mm Auto cartridges. Although the operation and functioning principles of the MP5/40 and MP5/10 are identical to the 9mm MP5, several user inspired improvements have been incorporated into the design, including a new bolt catch device that holds the bolt group rearward after the magazine is empty. Depressing the bolt catch releases the bolt to chamber the first round of a loaded magazine.New lightweight synthetic magazines are durable and ensure reliable feeding under the most extreme conditions. Like all MP5s, the MP5/40 and MP5/10 can be disassembled without tools for cleaning and maintenance. The firepower, penetration, and hard-hitting potential of a 10mm MP5 is greater than a .45 ACP Thompson submachine gun. At any range, the projectile fired from a 10mm MP5 has nearly twice the energy of a comparable 9mm, .40 S&W, or .45 ACP cartridge. In 1994, the US Federal Bureau of Investigation (FBI) adopted the MP5/10 as their new submachine gun.