For the Love of the MP5: Roller-Locked 9mm Clones

By Chris Eger

The PTR 9KT, a semi-auto send-up of the HK MP5K. What’s not to love? (Photo: Chris Eger/Guns.com)
The Heckler & Koch MP5 is a thing of enduring beauty but their rarity on the consumer market has left a void quickly filled by dozens of clones.
Developed in the 1960s as HKs Maschinenpistole 5 by a team led by Tilo Möller, the team essentially started with the company’s proven G3 battle rifle and, in many ways, just downsized the 9-pound 7.62x51mm weapon to a much smaller 5.5-pound, creating a 9x19mm chambered squirt gun.
Both guns share the same basic roller-delayed blowback action. The roller lock design, invented by Dr. Werner Gruner and used in WWII on the very successful MG42 machine gun, creates a durable and effective lock-up that is as efficient as it is reliable. The blowback action fundamentally treats the cartridge case itself like a piston to work the closed bolt, with the gas of the recoil being transferred through a fluted chamber.
A staple of military special ops types and counter-terror teams for decades, the MP5 today evokes the same sort of old-school cool common in Cold War-era SEAL teams.
SEAL Team 8 wielding the iconic H&K MP5 submachine gun in 1991 (Photo:

Source: Guns.com