Lower Troubleshooting

Heavy Trigger Pull in Super Safe Mode

Fix Options:

  • Lightly sand the rounded corner of the trigger using 220-grit sandpaper.
  • Maintain the curved shape and remove only minimal material.
  • After restoring function, polish the surface using 320-grit, 400-grit, or higher to reduce friction without altering the geometry.
Trigger Will Not Pull or Release Hammer in Super Safe Mode

Fix Options:

  • Sand the rounded corner of the trigger with 220-grit sandpaper.
  • Preserve the original curvature — avoid flat spots.
  • Polish the surface with finer grit (320–400+) to improve mechanical contact while maintaining the profile.
Safety Cam Switches Modes Without Input

Fix Options:

  • Inspect the safety detent for wear or flattening; replace if necessary.
  • Check the detent spring for damage or improper compression.
  • Add shim material under the detent spring to increase tension, or reduce tension by trimming coils (rare cases).
  • For M16-cut or wide pocket lowers, install a freely moving centering block to prevent cam misalignment.
  • If none of these resolve the issue, the cam may be out of spec — contact CFR.
Trigger Does Not Reset in Super Safe Mode

Fix Options:

  • Ensure the safety cam is in the center position.
  • Check for a high-shelf lower (see Picture 1). If identified, remove some material from behind the selector hole using a Dremel or mill.
  • If trigger was purchased from CFR and overcut is suspected, contact us for resolution.
Trigger or Hammer Pins Walking Out

Fix:

  • Always use Anti-Walk Pins with the Super Safety.
  • Do NOT use Anti-Rotation Pins, as they may cause malfunctions.
Trigger Fires in Safe Position

Fix Options:

  • Reinstall the kit from scratch to eliminate installation errors.
  • If the issue persists, contact CFR for technical support.

Upper Troubleshooting

Charging Handle or BCG Binds 3/4 to Rear

Fix Options:

  • Cut the rear shelf of the upper receiver to allow lever clearance (see Pictures 2 and 3).
  • If binding persists, very lightly grind down the flat top of the lever with 40–80 grit (not recommended unless absolutely necessary).
  • If over-travel is the issue, insert a longer buffer or place 1–4 quarters behind the buffer spring.
Trigger Locks Up After One Round

Fix Options:

  • Verify that a Full Auto BCG is installed. Semi Auto BCGs from Ruger or S&W may not actuate the lever.
  • Refer to Picture 4 for visual comparison of BCG types.
PCC Bolt Fails to Fully Close Into Battery

Fix:

  • Cut or replace the bolt weight to ensure it sits flush inside the bolt carrier.
  • See Picture 5 for a visual guide.

Live Fire Troubleshooting

Light Primer Strikes or Hammer Follows After <5 Rounds

Fix Options:

  • Use a heavier buffer (H3 or H4 recommended).
  • Adjust the gas block to reduce backpressure.
  • Swap the buffer spring for a higher-tension (enhanced power) spring.
Failure to Extract or Eject

Fix Options:

  • Adjust gas block or buffer/spring weight.
  • In MP5-style platforms, replace (in order): extractor spring, extractor, and ejector lever. Use HK-branded parts.
  • In K-model MP5s, use an 80° or 90° locking piece if bolt velocity is a factor.
  • Experiment with different ammo and suppressors.
OOB (Out of Battery) Detonations in PCCs

Fix Options:

  • Use a CMMG RDB system to replicate AR-15 locking lug design.
  • Increase total bolt + buffer weight to 23 oz or more.
  • KAK Industry tungsten bolt weight is a good pre-sized option.
Lever Snaps Within First 100 Rounds

Fix Options:

  • Reconfirm upper shelf cut was completed and bolt weight modified per instructions.
  • Inspect the lower shelf height — excess height can block rearward cam rotation and cause breakage.
  • If the lever failed due to material hardening, CFR will replace it — contact us.
Run Out of Ammo Too Quickly

Fix:

  • Buy more ammo.