Geissele 05-2991 Stress-Proof Bolt Assembly w/ExtractorThe Geissele Stress-Proof Bolt Assembly with Extractor 05-2991 is a high-performance bolt designed for reliability. It features a stress-proof steel construction, ensuring durability and strength under extreme conditions. This Geissele 05-2991 bolt assembly is rigorously tested, including high-pressure testing and magnetic particle inspection, making it a reliable choice for heavy-duty use. It's ideal for enhancing the performance of AR-15/M4 platforms. The Geissele Stressproof Bolt is part of their Reliability Enhanced Bolt Carrier Group. Each forged bolt undergoes thorough inspection, including high pressure testing, magnetic particle inspection, and is coated with Nanoweapon for enhanced durability and performance. Geissele Stress-Proof Bolt Assembly w/Extractor 05-2991