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Geissele Automatics Stress Proof Bolt Assembly Fits AR-15 Black 05-2991 UPC 810081134972
Product Description
The Geissele Automatics Stress Proof Bolt Assembly (05-2991) is an ultra-durable, high-performance 5.56mm/.223 Rem bolt engineered specifically to eliminate the primary failure points of standard AR-15 mil-spec bolts. Manufactured from Geissele's proprietary Carpenter 158+ steel, this bolt undergoes advanced forged metallurgy and heat-treatment processes to yield a material structure with superior fatigue life, tensile strength, and impact resistance under extreme firing schedules.
Precision CNC-machined to exact tolerances, the Stress Proof Bolt features redesigned, stress-relieved lug geometries that redistribute operational locking stress evenly across the bolt lugs, preventing premature lug shear common in suppressed or high-round-count carbines. Finished in a slick, high-lubricity black manganese phosphate coating, it resists severe heat, carbon fouling, and environmental corrosion while maintaining low friction inside the bolt carrier channel.
Completely assembled and ready for drop-in staging, the 05-2991 includes a heavy-duty extractor machined from stress-proof steel, paired with a high-tensile extractor spring and insert to guarantee violent, positive ejection under adverse conditions. Every bolt is individually High Pressure Tested (HPT) and Magnetic Particle Inspected (MPI) to ensure zero internal flaws or microscopic stress fractures before leaving the factory.
Armorer Bench Notes & Real-World Staging Guidance:
Fitment Matrix: Fits standard mil-spec AR-15, M4, and M16 bolt carriers (5.56 NATO, .223 Remington, and 300 AAC Blackout). Compatible with standard firing pins, cam pins, and retaining pins.
- Perform a complete firearm safety check: drop the magazine, pull the charging handle rearward, and visually inspect the chamber to ensure zero live rounds are present.
- Field strip the rifle by removing the upper receiver, charging handle, and bolt carrier group (BCG).
- Remove the firing pin retaining pin, drop out the firing pin, rotate the cam pin 90 degrees, and slide the old bolt out of the front of the carrier.
- Clean the interior cavity of the bolt carrier and apply a light coat of high-tier synthetic weapons lubricant to the tail and gas rings of the new Geissele Stress Proof bolt.
- Insert the Geissele Stress Proof bolt into the carrier with the extractor facing the right side (ejection port side), re-install the cam pin, firing pin, and retaining pin.
- Perform a manual function check: pull the bolt forward to confirm smooth gas ring compression and verify headspace using GO/NO-GO gauges before live fire.
Key Features
- Proprietary Carpenter 158+ Steel: Specially forged and heat-treated alloy delivers unmatched resistance to metal fatigue and high pressure.
- Stress-Relieved Lug Geometry: Precision-milled locking lugs redistribute stress to prevent shear and catastrophic bolt failure.
- Black Manganese Phosphate Finish: High-lubricity protective coating resists carbon buildup, friction, and environmental corrosion.
- Enhanced Heavy-Duty Extractor Assembly: Includes a stress-proof extractor with an upgraded spring assembly for ultra-reliable casing extraction.
- 100% HPT & MPI Inspected: Individually proof-tested under high pressure and magnetic particle inspected to guarantee structural purity.
- Drop-In Mil-Spec Compatibility: Seamlessly replaces standard bolt assemblies in any quality 5.56/.223 AR-15 bolt carrier.
Product Specifications
- Brand: Geissele Automatics
- Model/Series: Stress Proof Bolt Assembly
- MPN / SKU: 05-2991
- UPC: 810081134972
- Caliber Fitment: 5.56x45mm NATO / .223 Remington / 300 AAC Blackout
- Platform Fitment: AR-15 / M4 / M16
- Bolt Material: Carpenter 158+ Steel
- Finish / Color: Manganese Phosphate Black
- Testing: High Pressure Tested (HPT) / Magnetic Particle Inspected (MPI)
- Weight: 1.5 oz
- Country of Origin: USA
