INDIAN special armed forces use GLOCK 17 as their secondary arm.. glock pistol is Austrian origin and is not detectable by metal detectors as it is made of plastic (exclude rounds) It is a series of polymer - framed , short recoil operated, locked breech semi-automatic pistols designed and produced by Glock Ges.m.b.H., located in Deutsch-Wagram, Austria. These are also used by US law enforcement agencies and other security forces across the world. Operating mechanism: The Glock 17 is a 9mm short recoil-operated locked breech semi-automatic pistol that uses a modified Browning cam-lock system adapted from the Hi-Power pistol. The firearm's locking mechanism utilizes a linkless, vertically tilting barrel with a rectangular breech that locks into the ejection port cut-out in the slide. During the recoil stroke, the barrel moves rearward initially locked together with the slide approximately 3 mm (0.12 in) until the bullet leaves the barrel and chamber pressure drops