Making their debut at the 2010 SHOT Show, the fourth generation (Gen4) of Glock pistols incorporated many features that users had been asking for. From a design perspective, changes in ergonomics were the main focal point of this rendition. Additionally, a few subtle internal changes were made to Glock’s Safe Action Pistol. The Glock 19 Gen4, a 9 mm Luger compact-sized pistol features a rough-textured frame, interchangeable backstraps and enlarged magazine release. Internally, the guide rod assembly was changed to use dual-nested recoil springs.