Buy Glock 20 Gen 4 Semi-Automatic Pistol. The Glock 20 Gen4 delivers formidable force downrange with high accuracy over long distance. The use of Glock hi-tech polymer considerably reduces felt recoil even in this heavy caliber. For the hunting community this 10mm Auto is a reliable companion providing a safe and accurate finishing shot, even when hunting big game. The modular back strap system makes it possible to instantly customize its grip to accommodate any hand size. The reversible magazine catch makes it ideal for left and right-handed shooters.