Last Round Bolt Hold Open

The Last Round Bolt Hold Open (LRBHO) feature is an essential part of your firearm, enhancing both safety and efficiency. It holds the bolt open after the last round is fired, clearly indicating that the magazine is empty. This allows for faster reloading and reduces the risk of accidental discharge. If your LRBHO isn't working correctly, follow this troubleshooting guide to fix the issue.

Step-by-Step Troubleshooting Guide for LRBHO Issues

  1. Use a High-Quality OEM Glock Magazine
    • Check magazine condition: Over time, magazine springs can wear out. If the bolt doesn't hold open with one magazine, try using another OEM Glock magazine.
  2. Use Factory Ammunition
    • Avoid reloads or re-manufactured ammunition: Using factory ammunition ensures consistency and reliability, which is crucial for the proper functioning of the LRBHO.
  3. Verify Bolt Catch Spring Installation
    • Check the lower receiver: Ensure that the lower receiver has the lightened bolt catch spring installed. This spring comes pre-installed in our complete firearms and is included in the small bag inside the receiver box for lower receivers or receiver sets.
  4. Confirm Correct Buffer and Spring Usage
    • Refer to guidelines: Make sure you're using the recommended buffer and buffer spring. Check our Buffer and Buffer Spring page for detailed recommendations.
  5. Check Cycling Distance
    • Measure the distance: Manually lock the bolt to the rear, leaving the charging handle extended. Pull the charging handle rearward until it stops and measure the distance traveled. It should be a minimum of 1/4". If it's less, the BCG may not be traveling far enough to activate the LRBHO.
  6. Test Manual Charging
    • Perform a manual test: Charge the gun with an empty OEM Glock magazine and see if the bolt holds open.
  7. Inspect the Bolt Catch Mechanism
    • Remove the upper receiver: Insert an empty OEM Glock magazine and check if the bolt catch lifts completely. If it doesn't, follow the steps on our Cleaning Bolt Catch Spring & Detent page to ensure proper functionality.

Maintenance and Safety Tips

Regular maintenance and understanding your firearm's components are essential for optimal operation. Always prioritize safety and proper upkeep to ensure a reliable and enjoyable shooting experience. Remember: "Safety first, happy shooting later!"

By following these steps, you can troubleshoot and resolve most issues with your LRBHO feature, ensuring your firearm functions smoothly and safely.

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