Colt 6520 16" Pencil Barrel Tested | 30-Shot Groups & Inspection

Published on March 18, 2026
Duration: 5:33

This expert-level review of the Colt 6520 16" pencil barrel provides detailed technical analysis and performance data. The barrel, dated September 2003, features a chrome-lined bore, 1:7 twist, and hand-finished feed ramps. Testing with various ammunition types at 100 yards reveals its accuracy potential, with a 30-shot group of 2.123 MOA using Federal 77gr MatchKing and 3.449 MOA with PMC M855. The review also explores the impact of barrel nut torque on accuracy.

Quick Summary

The Colt 6520 16" pencil barrel, dated September 2003, features a 16-inch length, 5.56 NATO chamber, 1:7 twist, and chrome-lined bore. It achieved a 30-shot group of 2.123 MOA with Federal 77gr MatchKing and averaged 2363 fps muzzle velocity.

Chapters

  1. 00:00Colt 6520 Barrel Introduction & History
  2. 00:13Barrel Features & Construction Details
  3. 00:21Weight & Internal/External Measurements
  4. 00:46Bore Inspection via Borescope
  5. 01:15Federal MatchKing Test Setup & Process
  6. 02:00Federal MatchKing Velocity Results
  7. 02:11Federal MatchKing Accuracy Analysis
  8. 02:23Federal MatchKing 30-Shot Group Stats
  9. 02:39Federal MatchKing 10-Shot Breakdown
  10. 02:45Federal MatchKing Leaderboard Placement
  11. 02:53PMC X-Tac M855 Test & Shooting
  12. 03:29PMC X-Tac M855 Velocity Results
  13. 03:43PMC X-Tac M855 30-Shot Group Stats
  14. 03:49PMC X-Tac M855 10-Shot Breakdown
  15. 03:52PMC X-Tac M855 Leaderboard Placement
  16. 03:57ADI MatchKing & Barrel Nut Torque Test
  17. 04:32ADI MatchKing Velocity Results (Torque Test)
  18. 04:55ADI MatchKing Accuracy Analysis (Torque Test)
  19. 05:01ADI MatchKing 30-Shot Group Stats (Torque Test)
  20. 05:15ADI MatchKing 10-Shot Breakdown (Torque Test)
  21. 05:22ADI MatchKing Leaderboard Placement (Torque Test)

Frequently Asked Questions

What are the key specifications of the Colt 6520 16" pencil barrel tested?

The Colt 6520 barrel, dated September 2003, features a 16-inch length, 5.56 NATO chamber, 1:7 twist rate, and a chrome-lined bore. It weighs 1.388 lbs stripped and has a gas port diameter of 0.062 inches for a carbine-length system.

How accurate is the Colt 6520 16" pencil barrel with premium ammunition?

When tested with Federal Gold Medal 77gr Sierra MatchKing at 100 yards, the Colt 6520 16" pencil barrel achieved a 30-shot group size of 2.123 MOA and an average 10-shot group size of 1.6 MOA.

What was the muzzle velocity achieved with the Colt 6520 barrel?

The Colt 6520 16" pencil barrel produced an average muzzle velocity of 2363 fps with Federal Gold Medal 77gr Sierra MatchKing and 2849 fps with PMC X-Tac M855. These velocities were noted as relatively slow compared to other 16" barrels.

Does barrel nut torque affect the accuracy of the Colt 6520 barrel?

Testing with ADI World Class 69gr Sierra MatchKing showed minimal impact of barrel nut torque on the Colt 6520 barrel's accuracy. 30-shot groups were 2.549 MOA at 40 ft-lbs and 2.434 MOA at 20 ft-lbs, with 10-shot groups averaging 1.6 MOA and 1.7 MOA respectively.

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