Geissele Stress-Proof Bolt Assembly w/Extractor 05-2991 is a high-performance drop-in bolt assembly for AR-15/M4 platforms, engineered for extreme reliability and longevity.

This Geissele Stressproof bolt is machined from forged Carpenter 465 steel, often referred to as Carpenter 158+. Each bolt undergoes shot-peening, high-pressure testing, and magnetic particle inspection before it ships, catching material flaws early rather than leaving them to surface in service. A proprietary Nanoweapon coating finishes the bolt for outstanding corrosion and wear resistance.

This Geissele Bolt includes an extractor made from premium 300M stainless steel, also Nanoweapon-coated for consistent function and enhanced durability. It fits AR-15/M4 platforms chambered in .223 Rem, .223 Wylde, 5.56 NATO, and .300 Blackout, weighing approximately 1.54 oz fully assembled.

Key Features:

• Forged Carpenter 465 (158+) steel bolt
• 300M stainless steel extractor, Nanoweapon-coated
• Shot-peened, high-pressure tested, magnetic-particle inspected
• Nanoweapon coating on bolt and extractor
• Compatible with .223 Rem, .223 Wylde, 5.56 NATO, .300 Blackout
• Weight: approximately 1.54 oz fully assembled
• Includes extractor spring, O-ring insert, ejector, ejector spring & pin
• Drop-in replacement for AR-15/M4 platforms

This AR-15 bolt assembly replaces one of the most failure-prone parts of an AR build with a bolt built to outlast the rifle around it.