Molded Plastic Boosts the Glock’s Profile

The cover headline on the January 24 issue of Time magazine is, "Guns. Speech. Madness. Where we go from Arizona."

The Glock handgun is again a focal point of a horrific shooting spree in America. Proponents of tougher gun laws are targeting the Glock and other weapons that are readily accessible, easy to use, lightweight and powerful.

"Enhanced lethality, that's what we are talking about," Tom Diaz, senior policy analyst at the Violence Policy Center, told the New York Times. "Lethality increases when you have larger bullets, more ammunition and the guns are easier to operate. That's the contribution Glock and others have brought to America."

The Glock is different, and the reason why is an interesting materials' engineering story.

The gun was invented by an engineer named Gaston Glock who was an Austrian expert in polymer manufacturing. In the late 1970's Glock ran a company that produced munitions, such as plastic grenade shells, for the Austrian army.  

The Austrian army was looking for a robust combat handgun and posted the following requirements for bidders:
1.The design has to be self-loading.
2. The pistol must fire the NATO-standard 9x19 mm Parabellum round.
3. The magazines would not require any means of assistance for loading.
4. The magazines must have a minimum capacity of eight rounds.
5. All actions necessary to prepare the pistol for firing and any actions required after firing must be done single-handed, either right- or left-handed.
6. The pistol must be absolutely secure against accidental discharge from shock, stroke and drops from a height of 2 m onto a steel plate.
7. Disassembly of the main parts for maintenance and reassembling must be possible without the use of any tools.
8. Maintenance and cleaning of the pistol must be accomplished without the use of tools.
9. The pistol's construction may not exceed 58 individual parts (equivalent of a P38).
10. Gauges, measuring and precise testing devices must not be necessary for the long-term maintenance of the pistol.
11. The manufacturer is required to provide the Ministry of Defense with a complete set of engineering drawings and exploded views. These must be supplied with all the relevant details for the production of the pistol.
12. All components must be fully interchangeable between pistols.
13. No more than 20 malfunctions are permitted during the first 10,000 rounds fired, not even minor jams that can be cleared without the use of any tools.
14. After firing 15,000 rounds of standard ammunition, the pistol will be inspected for wear. The pistol will then be used to fire an overpressure test cartridge generating 5,000 bar (72,518 psi). The critical components must continue to function properly and be up to specifications, otherwise the pistol will be disqualified.
15. When handled properly, under no circumstances may the user be endangered by case ejection.
16. The muzzle energy must be at least 441.5 J when firing a 9mm S-round/P-08 Hirtenberger AG.
17. Pistols scoring less than 70 percent of the total available points will not be considered for military use.

Glock designed and built a prototype of his first handgun in the early 1980s. In a major departure, he made several parts of the gun from plastic, a novel idea that made the gun much lighter and resistant to salt in perspiration-a major issue for the durability of a handgun. The plastic also provided some give, easing the recoil of the gun.

Glock is very secretive about engineering details of his gun design, but some information is available from patent filings and a handful of interviews he has given to gun enthusiasts.

According to these sources, he invented a proprietary polymer formulation based on polyamide (nylon) reinforced with glass. The plastic parts are more than 80 percent lighter than comparable parts made from metal.

Plastic molding provides an opportunity for design details not possible with a metal frame. For example, the molded Glock frame features four guide rails. Molded-in functionality also meant that the Glock had far fewer parts than comparable guns. As a result, there was less opportunity for malfunction and the gun was easy to take apart and reassemble.

Even the metal parts in the Glock are special.

A ferritic nitrocarburizing is used to treat the steel barrel and slide to provide wear and corrosion resistance. The gun has been redesigned many times since its introduction.

The creative materials' engineering and mechanical design have made the Glock a big winner with armed forces and police departments. It's estimated that two of three handguns used by American law enforcement officials are Glocks.