| Please click here to visit the "Military Rifle Components Guide" for additional info and photos of the various components used on this model. |
HISTORY / BACKGROUND:
The Colt Model 604 was the AR-15/M-16 model developed primarily for the US Air Force. It differed from the
XM16E1 and M16A1 in that it did not have the forward assist feature. The "early" models were built with a
Partial Fence Lower and 3-Prong Flashhider, and the "late" models were built with Full Fence Lowers and
A1 Birdcage Flashhiders.
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The Colt Model 604 was the AR-15/M-16 model developed primarily for the US Air Force. It differed from the
XM16E1 and M16A1 in that it did not have the forward assist feature. The "early" models were built with a
Partial Fence Lower and 3-Prong Flashhider, and the "late" models were built with Full Fence Lowers and
A1 Birdcage Flashhiders.
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BUTTSTOCK:
STYLE:
Later / Improved Solid Body
Type D
BUTTPLATE:
Solid Rubber
SWIVEL:
Pinned, Metal with
Plastic Covering
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BUFFER GROUP:
BUFFER:
Early - Edgewater Spring Guide
Late - Improved / Current Rifle Buffer
SPRING:
Standard Rifle Spring
TUBE:
Early - Original Tube, without Wrench Flats
Late - Improved Tube, with Wrench Flats on the End
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LOWER RECEIVER:
STYLE:
Early - "Partial Fence"
Late - "Full Fence"
MARKINGS:
Colt Logo
COLT AR-15
PROPERTY
OF U.S. GOVT.
M 16
CAL. 5.56 MM.
Serial XXXXXX
SELECTOR:
"Later"
TAKEDOWN / PIVOT PINS:
"Later" Pins
BOLT CATCH/RELEASE:
"Latter" with Raised/Grooved End
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UPPER RECEIVER:
PROOF MARKS / FORGE CODE:
Colt Proof Marks - Triangle & Square with "C"
Located in front of ejection port
No Forge Code
REAR SIGHT:
EJECTION PORT COVER:
"Later" with " Rectangular Plate"
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BOLT GROUP:
CARRIER:
Early - Possible Transitional Bolt, Mix of Parts
Late - Parkerized with Forward Assist Serrations
BOLT:
Chrome or Parkerized
FIRING PIN:
Improved Light Flat Head
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CHARGING HANDLE:
Current Improved Design
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HANDGUARD SLIP RING:
Flat
______________________________________________________________________________________________________
BARREL:
DIAMETER:
0.625" at the Front Sight Base
LENGTH:
20"
TWIST RATE:
1/12
MARKINGS:
______________________________________________________________________________________________________
HANDGUARDS:
Standard Triangular
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FRONT SIGHT BASE:
STYLE:
Forged
MARKINGS:
None
______________________________________________________________________________________________________
FLASHHIDER:
Early - Improved 3 Prong Flashhider
Late - A1 Birdcage
STYLE:
Later / Improved Solid Body
Type D
BUTTPLATE:
Solid Rubber
SWIVEL:
Pinned, Metal with
Plastic Covering
______________________________________________________________________________________________________
BUFFER GROUP:
BUFFER:
Early - Edgewater Spring Guide
Late - Improved / Current Rifle Buffer
SPRING:
Standard Rifle Spring
TUBE:
Early - Original Tube, without Wrench Flats
Late - Improved Tube, with Wrench Flats on the End
______________________________________________________________________________________________________
LOWER RECEIVER:
STYLE:
Early - "Partial Fence"
Late - "Full Fence"
MARKINGS:
Colt Logo
COLT AR-15
PROPERTY
OF U.S. GOVT.
M 16
CAL. 5.56 MM.
Serial XXXXXX
SELECTOR:
"Later"
TAKEDOWN / PIVOT PINS:
"Later" Pins
BOLT CATCH/RELEASE:
"Latter" with Raised/Grooved End
______________________________________________________________________________________________________
UPPER RECEIVER:
PROOF MARKS / FORGE CODE:
Colt Proof Marks - Triangle & Square with "C"
Located in front of ejection port
No Forge Code
REAR SIGHT:
EJECTION PORT COVER:
"Later" with " Rectangular Plate"
______________________________________________________________________________________________________
BOLT GROUP:
CARRIER:
Early - Possible Transitional Bolt, Mix of Parts
Late - Parkerized with Forward Assist Serrations
BOLT:
Chrome or Parkerized
FIRING PIN:
Improved Light Flat Head
______________________________________________________________________________________________________
CHARGING HANDLE:
Current Improved Design
______________________________________________________________________________________________________
HANDGUARD SLIP RING:
Flat
______________________________________________________________________________________________________
BARREL:
DIAMETER:
0.625" at the Front Sight Base
LENGTH:
20"
TWIST RATE:
1/12
MARKINGS:
______________________________________________________________________________________________________
HANDGUARDS:
Standard Triangular
______________________________________________________________________________________________________
FRONT SIGHT BASE:
STYLE:
Forged
MARKINGS:
None
______________________________________________________________________________________________________
FLASHHIDER:
Early - Improved 3 Prong Flashhider
Late - A1 Birdcage
| 1967 - Vietnam US Navy "Brown Water" Patrol |
RETRO BLACK RIFLE - RIFLE GUIDE - MODEL 604
 | |  | |  | |  | |  | |  |
| Unknown Date - Vietnam US Navy |
| Unknown Date - Vietnam |
| Oct 1989 - Eglin AFB, FL Sgt. Lee of the base's security police issuing a M-16 rifle. This is also an early Model 604 with various upgrades. |
| _________________________________________________________________________________ ADDITIONAL COLT MODEL 604 INFORMATION |
| Oct 1981 - Osan Air Base, KOR Senior Airman Malerva, 432nd Security Police Squadron, during the ground base defense exercise Foal Eagle '91. This is an "early" Model 604 with the Partial Fence Lower, but the Flash Hider has probably been upgraded from an Improved 3 Prong to an A1 Birdcage. |
| June 1984 - Camp Robinson, AR Sergeant Peterson, from the 314th Security Police Squadron participates in Exercise SAFE DEFENDER ONE as a member of the aggressor force. This is a "late" Model 604, as indicated by the Full Fence Lower. |
| January 1984 - Little Rock Air Base, AR Airman Donald during Exercise VOLANT SCORPION. This is also an example of a "late" Model 604. |
| .223 Cal / 5.56mm MILITARY RIFLE GUIDE |
