Hoffman Super Safeties are compatible with AR15 rifles chambered in 9mm (AR9). Below are key requirements and tips to ensure proper function.
Key Measurement
The rear of the Bolt Carrier Group (BCG) must measure 1.57" for the safety to work correctly.
Important Note
Avoid using a Foxtrot Mike FM9 BCG with a Super Safety, as it often causes a "failure to fire" issue. This may be due to the firing pin design.
AR9-Specific Issue: BCG Weight Interference
Problem:
Some AR9 BCGs have an internal weight that sticks out past the lower edge of the BCG. This can contact the safety lever as the bolt nears the closed position, causing binding or even breaking the lever.
Solution:
Remove the Weight:
Most AR9 BCG weights are secured with a roll pin. Use a hammer and punch to knock out the roll pin and remove the weight.
Trim the Weight:
Trim the weight to ensure it doesn’t extend past the BCG’s lower edge, creating clearance for the lever to move freely. The weight should be cut at least 4mm or 5/32" deep , this is measured with the weight removed from the BCG
Reinstall the Weight:
After trimming, reattach the weight by reversing the removal process (insert the weight and secure it with the roll pin).
Tips for Success
Double-check the BCG measurement (1.57") before installation.
Ensure the trimmed weight doesn’t interfere with the lever’s movement.
If you experience binding or other issues, verify that the lever moves freely and isn’t obstructed by the BCG weight.