Sig AMT Disassembly

Published on October 17, 2011
Duration: 14:40

This comprehensive guide details the disassembly and reassembly of the Sig AMT, the civilian variant of the Swiss STG 57. Expert instruction covers the unique roller-locked action, trigger group, and bolt assembly, highlighting key differences between semi-automatic and full-automatic variants. The video emphasizes the robust design, suitable for the .308 cartridge, and offers insights into its historical context and mechanical intricacies.

Quick Summary

The Sig AMT, a civilian version of the Swiss STG 57, features a robust roller-locked action designed for the .308 cartridge. Its disassembly involves removing the stock, charging handle, bolt, and trigger assembly. Key technical aspects include a removable locking shoulder for repairs and headspace adjustment, and larger rollers compared to designs like the HK91, ensuring enhanced safety and durability.

Chapters

  1. 00:15Introduction to Sig AMT
  2. 00:47Roller-Locked Action Explained
  3. 01:09Stock and Recoil Spring Removal
  4. 01:39Charging Handle and Bolt Assembly
  5. 02:05Trigger Assembly Removal
  6. 02:35Trigger Characteristics
  7. 03:02Upper Receiver and Barrel
  8. 03:24Removable Locking Shoulder
  9. 03:55Fire Control Group Comparison
  10. 05:00Bolt Assembly Comparison
  11. 06:04Extractor Spring Mechanism
  12. 06:24Bolt Disassembly
  13. 06:56Roller Lock Comparison (AMT vs. HK91)
  14. 08:03Roller Lock Design for .308
  15. 08:21Unusual Firing Pin Mechanism
  16. 09:00Muzzle and Front Sight Differences
  17. 09:52Bipod Features
  18. 10:15Caliber Variations and Magazines
  19. 11:18Rifle Reassembly
  20. 13:01Ergonomics and Shooting Impressions
  21. 13:29Sights and Accuracy
  22. 14:00Ergonomic Complaint and Conclusion

Frequently Asked Questions

What is the Sig AMT and its relation to the STG 57?

The Sig AMT is the civilian variant of the Swiss military's STG 57 rifle. Both feature a distinctive roller-locked action, designed without a gas system, drawing influence from German weapon designs.

How is the roller-locked action of the Sig AMT different from other designs like the HK91?

The Sig AMT utilizes significantly larger rollers and camming surfaces compared to the HK91. This robust design was specifically engineered for the .308 cartridge to ensure safety and durability, whereas the HK91's system was adapted from designs for less powerful rounds.

What are the key components involved in Sig AMT disassembly?

Disassembly of the Sig AMT involves removing the stock assembly, charging handle, bolt assembly, and trigger assembly. The trigger assembly is secured by a captive pin that allows the housing to rotate down for removal.

Does the Sig AMT have a removable locking shoulder, and why is it important?

Yes, the Sig AMT features a removable locking shoulder. This component is crucial for repair of worn parts or headspace adjustment, offering a significant advantage over designs that rely on different sized rollers for these functions.

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