Colt SMG: First of the 9mm ARs

Published on August 8, 2025
Duration: 13:32

This guide details the field stripping process for the Colt SMG (Model 635), a 9mm submachine gun based on the AR-15 platform. It covers the removal of key components like the bolt carrier group, buffer, recoil spring, bolt, and charging handle. The information is presented with a high level of technical detail, reflecting the expertise of the presenter.

Quick Summary

The Colt SMG (Model 635) is a 9mm submachine gun built on the AR-15 platform, featuring a simple blowback action and controls identical to M16 rifles. Developed to compete with the HK MP5, it uses modified Uzi magazines and incorporates features like a gas deflector and stainless steel fire control pins for durability.

Chapters

  1. 00:00Introduction and Context
  2. 01:13Early Development and Prototypes
  3. 02:31Rate of Fire and Mechanical Changes
  4. 03:23Receiver Markings and Serial Numbers
  5. 04:04Magazine Design and Modifications
  6. 05:13Gas Deflector and Dust Cover
  7. 06:07Internal Blowback System
  8. 07:38Lower Receiver and Magazine Adapter
  9. 09:18Fire Control Group Upgrades
  10. 09:53Market Performance and Variants

Frequently Asked Questions

What makes the Colt SMG a 9mm AR-15 variant?

The Colt SMG (Model 635) is based on the AR-15 platform, sharing its lower receiver and controls. However, it uses a simple blowback system instead of direct impingement and is chambered in 9mm NATO, requiring specific modifications like a magazine adapter and bolt carrier group.

How did Colt modify Uzi magazines for the SMG?

Colt adapted 25 and 32-round Uzi magazines by adding a notch for the AR-style magazine release and a tab on the follower. This tab activates the bolt hold-open feature, which the original Uzi magazines lacked.

What is the significance of the 'HT' serial number prefix on the Colt SMG?

The 'HT' prefix on the serial number of a Colt SMG indicates that it is a full-automatic variant, named after senior engineer Henry Tatro. These models are subject to NFA regulations in the United States.

Why was a gas deflector added to the Colt SMG?

A distinctive plastic gas deflector was added to the Colt SMG in 1986 to protect the shooter from ejected gas and brass. This modification required shortening the standard AR-15 dust cover to accommodate the altered ejection port area.

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