Stressproof Bolt Assembly with Extractor

Geissele Stressproof Bolt Assembly with Extractor

The Geissele Stressproof Bolt is made from Carpenter 158, but this is not a typical material specified by the U.S. government. Since Geissele wanted to take it to the next level, our engineers worked directly with the metallurgists at Carpenter Steel in Reading, PA, to produce a special grade of the material known as Carpenter 158+. This material is purer and contains fewer impurities, which ultimately makes it stronger and more durable. But that’s not all: we decided to forge the bolt. Using the same process employed to manufacture upper and lower receivers, forging the bolt head manipulates the metal’s grain structure. This results in a service life five times longer than that of a Mil-Spec bolt. Each bolt head is then rigorously inspected, pressure-tested, magnetically particle-inspected, and coated with Nanoweapon for maximum corrosion and wear resistance.