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HISTORY / BACKGROUND:-
The Colt Model R6000 was built incorporating the first round of changes / improvements. (Flashhider,
Charging Handle, Lower Components) It is similar in appearance to the Military 604 except it has a
slabside lower.
It was first release in January 2, 1964.
Production of the SP1 series ended in late 1982 with the introduction of the Sporter II series.

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BUTTSTOCK:
STYLE:
Early: Improved Solid Body Type D
Late: Trap door Type E

BUTTPLATE:
Early: Solid Rubber
Late: Solid One Piece Plastic

SWIVEL:
Pinned, Rubber Coated Metal

Body:
Early: Solid
Late: Hollow storage compartment

SCREW:
Early: Short A1 screw (no-hole)
Late: Short A1 screw, with hole

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BUFFER GROUP:
BUFFER:
Early: "Original" Edgewater Design
Late: Improved / current rifle buffer

SPRING:
Standard Rifle Spring

TUBE:
Early: Original Tube, No wrench flats, Hole in tube at receiver end to tighten tube
Late: Current buffer tube

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LOWER RECEIVER:
STYLE:
Slabside"

MARKINGS:
(Colt Logo) Colt
AR15

Model Sp1
Serial SP XXXXX

TAKEDOWN / PIVOT PINS:
Early: "Original" Takedown Pin with "Divot" in Center
Late:
Large Screw Pivot Pin

SELECTOR:
Early: "Original" with Hole in Center
Late: "Later"

MAGAZINE RELEASE BUTTON:
Later/Improved with Circular Line Pattern

BOLT CATCH/RELEASE:
"Original" with Flat End

OTHER:
Milled selector stops

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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:
Directional Markings on receiver
are raised

EJECTION PORT COVER:
"Later" with " Rectangular Plate"
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BOLT GROUP:
CARRIER:
Early: Manganese Phosphate Finish Slickside
Late: Manganese Phosphate Finish with Forward Assist Serrations

BOLT:
Early: Chrome
Late: Manganese Phosphate Finish

FIRING PIN:
Early: "Original" Heavy Flat Head
Retained with "Original" Machined Pin

Late: Improved Light Flat Head
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CHARGING HANDLE:
Early: Original Triangular

Late: - Current Improved Design

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HANDGUARD SLIP RING:
Flat

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BARREL:
DIAMETER:
0.625" at the Front Sight Base

LENGTH:
20"

TWIST RATE:
1/12

MARKINGS:
Colt Proof Marks between the FSB Legs
"12" approx 1" from the Flashhider

Note: Early barrels were not chromed.

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HANDGUARDS:
Standard Triangular,
Early: Without Drain Holes
Late: With Drain Holes

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FRONT SIGHT BASE:
STYLE:
Early: Cast
Late: Forged

MARKINGS:
None

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FLASHHIDER:
Early: Improved 3 Prong
Late: A1 Birdcage

RETRO BLACK RIFLE - CIVILIAN GUIDE - MODEL 6000