The INSAS (Indian Small Arms System) rifle is the standard infantry weapon of the Indian Armed Forces, designed and manufactured by the Ordnance Factories Board (OFB), India. It was developed to replace the older Ishapore 7.62mm SLR (Self-Loading Rifle) and 9mm Sterling Carbine. Below is a detailed breakdown of its parts and features:

 

1. Overview of INSAS Rifle

- Type: Assault Rifle / Battle Rifle 

- Caliber: 5.56×45mm NATO 

- Action: Gas-operated, Rotating bolt 

- Rate of Fire: ~650 rounds/min (cyclic) 

- Effective Range: 400-450 meters 

- Feed System: 20/30-round detachable box magazine 

- Muzzle Velocity: ~900 m/s 

- Weight: ~4.25 kg (unloaded) 

- Length: 945 mm (fixed stock), 960 mm (folded stock) 

- Barrel Length: 464 mm 

- Sights: ** Adjustable iron sights (rear aperture, front post) 

 

2. Major Parts of INSAS Rifle

 

A. Barrel Assembly

1. Barrel – Rifled, chrome-lined for durability. 

2. Gas Block – Regulates gas pressure for cycling. 

3. Flash Hider – Reduces muzzle flash. 

4. Front Sight Post – Adjustable for elevation. 

 

B. Upper Receiver

5. Bolt Carrier Group (BCG)

   - Bolt – Rotating locking mechanism. 

   - Firing Pin – Strikes the primer. 

   - Extractor & Ejector – Removes spent cartridges. 

6. Dust Cover – Protects internal mechanism. 

 

C. Lower Receiver

7. Trigger Mechanism – Includes: 

   - Trigger – Fires the weapon. 

   - Hammer – Strikes the firing pin. 

   - Selector Switch – Safe/Semi-Auto/3-round burst (some variants). 

8. Pistol Grip – Ergonomically designed for better handling. 

 

D. Stock & Butt Assembly

9. Fixed/Folding Stock – Made of polymer or metal. 

10. Recoil Pad – Reduces shoulder impact. 

 

E. Magazine

11. 20/30-round Magazine – Made of steel or polymer. 

12. Magazine Release – Detaches the magazine. 

 

F. Sights

13. Rear Sight – Adjustable aperture sight. 

14. Front Sight – Post-type with protective wings. 

 

G. Gas System

15. Gas Tube – Directs gas pressure to cycle the action. 

16. Gas Regulator – Adjustable for different conditions. 

 

H. Handguard

17. Polymer Handguard – Protects the barrel and provides grip. 

 

I. Other Components

18. Charging Handle – Used to manually cycle the bolt. 

19. Sling Swivels – For attaching carrying slings. 

20. Bayonet Lug – Allows mounting of a bayonet. 

 

3. Variants of INSAS Rifle

1. INSAS 1B1 – Standard infantry rifle (fixed stock). 

2. INSAS 1B2 – Folding stock variant for paratroopers. 

3. Excalibur – Improved version with better ergonomics. 

4. INSAS LMG – Light Machine Gun variant with a longer barrel and bipod. 

5. Trichy Assault Rifle (TAR) – A modernized version with Picatinny rails. 

 

4. Features & Modifications

- Three-round burst mode (earlier models). 

- Ambidextrous controls (later variants). 

- Compatibility with NATO 5.56mm magazines (Excalibur). 

- Picatinny rails (for optics & accessories in newer models). 

 

5. Issues & Improvements

- Initial problems with cold weather performance and magazine cracking. 

- Upgraded variants (Excalibur, Trichy) addressed these issues. 

- Gradual replacement by AK-203 & SIG-716 in some units.