The Gen 2 Sig MCX Virtus

Published on October 17, 2018
Duration: 21:57

This guide details the process of changing the barrel and caliber on the Sig MCX Virtus platform, covering the transition between 5.56 NATO and .300 Blackout. It emphasizes the use of specific tools like a torque wrench with a limiter and highlights the importance of safety during disassembly and reassembly. The video demonstrates how the modularity of the MCX Virtus allows for quick caliber changes by swapping barrels and ensuring proper reassembly.

Quick Summary

The Sig MCX Virtus allows for caliber conversion, typically between 5.56 NATO and .300 Blackout, by swapping barrels. This process requires removing the handguard and two Torx bolts securing the barrel, then installing the new barrel and re-torquing the bolts to 60 inch-pounds using a specialized torque wrench.

Chapters

  1. 00:01Introduction to Sig MCX Virtus
  2. 00:30Original 2015 MCX Features
  3. 00:50Operating System: Short-Stroke Piston
  4. 01:10Charging Handle and Flash Suppressor
  5. 01:20Barrel Specs: 16-inch, 1:7 Twist
  6. 01:27Handguard: KeyMod (Original)
  7. 01:35Fire-Control Mechanism and Lower Receiver
  8. 01:45AR-15 Lower Receiver Conversion Kit
  9. 01:56Updates: Pistol Grip & Magazine Release
  10. 02:19Ambidextrous Controls & Bolt Catch
  11. 02:28QD Attachment Points
  12. 02:33Optic: Sig ROM 807 Red Dot
  13. 02:46Transition to Sig Virtus
  14. 02:55Original MCX Bolt Carrier Recall
  15. 03:15Enhanced Bolt Carrier Group
  16. 03:22System Design: .300 Blackout to 5.56 Conversion
  17. 03:38Barrel Interchangeability Issues
  18. 04:02Virtus Gas Blocks: 5.56 vs. .300 BLK
  19. 04:31Introduction to 2018 Sig Virtus
  20. 04:40Virtus Changes: Long Handguard
  21. 05:01Handguard: M-LOK (Virtus)
  22. 05:07Virtus Stock: Telescopic 6-Position
  23. 05:18MP5 Type Telescopic Stock Option
  24. 05:24Trigger Compatibility: Firing Pin Block
  25. 05:41Geissele & Sigmax Triggers
  26. 05:50Pistol Grip: Drop Angle
  27. 06:12Stealth Gray Finish
  28. 06:22Back to Front Comparison
  29. 06:32Cold Hammer Forged Barrel: Nitride Coated
  30. 06:36Virtus Flash Suppressor
  31. 06:40Gas Valve Adjustment: 5.56 & .300 BLK Ports
  32. 06:56Gas Piston Adjustment Valve
  33. 07:04Continuous 1913 Rail
  34. 07:08Rear QD Points & Ambidextrous Safety
  35. 07:12Trigger Guard & Takedown Pins
  36. 07:21Bolt Carrier Group Assembly
  37. 07:25Recoil Spring Assembly: Steel vs. Polymer
  38. 07:42Firing Pin Block Assembly
  39. 08:06Trigger Requirements: Mil-Spec, Geissele, Sigmax
  40. 08:28Dogleg Type Way: Stronger BCG
  41. 08:43Original BCG Piston Removal
  42. 08:57Disassembly Demonstration
  43. 09:02Captive Firing Pin Retaining Pin
  44. 09:12Removing Firing Pin
  45. 09:33Removing Bolt Carrier
  46. 09:40Bolt Design: Rounded Lugs
  47. 09:55Maximum Disassembly Level
  48. 10:01Recoil Spring Assembly
  49. 10:08Reassembly: Bolt Carrier
  50. 10:22Reassembly: Firing Pin and Block
  51. 10:40Securing Firing Pin Retaining Pin
  52. 10:46BCG for 5.56 and .300 BLK
  53. 10:54Upper/Lower Receiver Separation
  54. 11:04Lower Receiver Differences
  55. 11:09Sig Trigger Grip Design
  56. 11:22Upper Receiver Overview
  57. 11:24Handguard Removal
  58. 11:33Handguard Length Options
  59. 11:40Barrel Removal Process
  60. 11:45Barrel Torx Bolts
  61. 11:50Borka Tools Torque Wrench
  62. 12:00Torquing Procedure
  63. 12:42Barrel Extraction
  64. 12:46Barrel Differences: .300 BLK vs. 5.56
  65. 12:53Operating Rod Length Comparison
  66. 13:11Extractor Guard Pin
  67. 13:30Switching to 5.56 Conversion
  68. 13:35Inserting 5.56 Barrel
  69. 13:46Tightening Procedure
  70. 14:16Reinstalling Handguard
  71. 14:38Locking Handguard Tab
  72. 14:42Installing Barrel Nut/Lock
  73. 14:50Charging Handle Reinstallation
  74. 15:00Alternative Charging Handle
  75. 15:11Charging Handle Tab Engagement
  76. 15:24Rifle Converted to 5.56
  77. 15:30Sig Bravo 4 Scope
  78. 15:341913 Rail and Red Dot
  79. 15:38Illuminated Reticle Adjustment
  80. 15:44Virtus vs. MPX Patrol Comparison
  81. 15:52Updates Not Seen on MCX
  82. 15:58Personal Preference in Choice
  83. 16:01Range Test and Barrel Change Demo
  84. 16:13Converting Virtus to .300 Blackout
  85. 16:18Separating Upper and Lower Receivers
  86. 16:32Handguard Removal (Range Test)
  87. 16:43Borka Wrench Usage
  88. 18:15Converted to .300 Blackout
  89. 19:35Reliability and Military Following
  90. 19:41Special Forces and Law Enforcement Use
  91. 19:55Special Forces Type Weapon
  92. 20:01General Purpose and Modularity
  93. 20:03Changing Barrels, Calibers, Lengths
  94. 20:17Future Caliber Possibilities
  95. 20:24Current Focus: 5.56 and .300 Blackout
  96. 20:28Available Barrel Lengths: MCX AX
  97. 20:34Available Barrel Lengths: Virtus
  98. 20:38Stock Options
  99. 20:42Standard Side Folding Stock
  100. 20:46AR-15 Stock Adapter
  101. 20:55MSRP: Gen 2 Virtus
  102. 21:05Weight: 7.9 Pounds
  103. 21:12Impressive Design
  104. 21:19Personal Preference: Original vs. Virtus
  105. 21:27Preference for Black Finish & Shorter Handguard
  106. 21:35Preference for M-LOK
  107. 21:38Future Stock Options for Original Patrol
  108. 21:44Video Conclusion

Frequently Asked Questions

What are the key differences between the original Sig MCX and the Virtus model?

The Sig MCX Virtus features a longer M-LOK handguard compared to the original's KeyMod. It also incorporates a bolt carrier group with a firing pin block for enhanced safety and uses different barrel designs that are not interchangeable between the two models due to gas block placement and operating rod variations.

How do you change the caliber on a Sig MCX Virtus?

Changing the caliber on a Sig MCX Virtus involves removing the handguard and then the barrel. You then swap in a barrel designed for the desired caliber (e.g., .300 Blackout or 5.56 NATO), ensuring the operating rod aligns correctly. The barrel is secured with two Torx bolts torqued to 60 inch-pounds.

What tools are needed to change the barrel on a Sig MCX Virtus?

To change the barrel on a Sig MCX Virtus, you will need a set of Torx bits and a torque wrench specifically set to 60 inch-pounds. A specialized wrench, like one from Borka Tools, is recommended as it often includes this torque limiter for precise installation.

Why is the bolt carrier group different on the Sig MCX Virtus compared to an AR-15?

The Sig MCX Virtus bolt carrier group is different because it incorporates a short-stroke gas piston system with integrated recoil springs, eliminating the need for a buffer tube. It also features a firing pin block to prevent slam-fires, which requires specific trigger compatibility.

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