Colt Firearms Collector
Preserving our American history

There is often confusion on internet sales pages where Colt optics are posted.  This information below is a combination of photos from my personal collection and my personal aggregated research notes obtained under the fair use doctrine and not copyrighted.

Colt 3x20 and 4x20 comments from LooseRounds.com:

The colt 3�20, and later 4x20, scopes were one of the first optics designed specifically for the AR15/M16 and were used during the Vietnam war.

Colt AR-15 rifles with bundled 3 x 20 scopes:

R6002

AR-15 Sporter (SP1; Bundled with 3� scope)

R6003

AR-15 Sporter Carbine (SP1 Carbine; Bundled with 3� scope)

The optic attaches to the carry handle by using the hole in the center. A threaded post protrudes out the bottom of the scope and a rotating lever is used to tighten the assembly to the underside of the handle, securing it tightly to the carry handle slot.

Once the optic is installed, the iron sights on the rifle or carbine can still be used.

The optics have a BDC turret that can be used after finer zeroing at 100 yds is done. To do this you remove the top cover to gain access to the finer adjustment screw.  Windage adjustment is on the right side of the scope body and can be adjusted after removing its cover.  Adjustment values are 1/4 inch per click. The rear of the optic is adjustable for parallax.

 
Once the optic is zeroed at 100 yards, the BDC can be used for fast and easy range adjustments.
The optic is calibrated for the M193 military load which is the 55 grain bullet.

 

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3 x 20 and 4 x 20 Carry Handle mounted scopes

There are four variations of the 3x20 and 4x20 Colt optics.  They range from the earliest (Made in U.S.A by Realist) marked Colt optic to later (Japanese) scopes made for Colt in Japan.  At the time these later Japanese optics were made in the 1970-90 range, the Japanese makers (Hakko Optics for Colt's later 3x and 4x optics) were the main lens optic suppliers to the U.S. market.  Witness the flood of fine Japanese photography products during those years and since to understand why Colt selected Japan to supply these scopes.

See: Colt 'Realist' 3 x 20 Sporter scope

3x20 left        vs       4x20 right

Various views of the mounting brackets and optic ends

The 4 x 20 lens is tinted blue

• Slotted screws are correct, not Phillips head.

• 4 x 20, not 4x20 (Space between numbers and the �X�).

• The range selection knob reads "YARDx100", not "YARDSx100" with an S.

• The windage knob is on the right side, a little behind the midpoint of the scope.

• The Colt logo is on the (front) objective end and faces the (rear) ocular end of the scope.

• The Colt (R) is at the upper right corner of the logo (above and to the right of the "T") and it is in parenthesis.

• The range selection knob on a real one sits further back than on this one. It should be back where it's partly over the rear "arm" of the mount�noticeably behind the windage knob on the side

• The original "bra" cover end caps are a vinyl fabric with red fleece lining, not the plastic see-through type used on the 4x21 scope, and the elastic straps are flat, not round elastic string as used on the 4x21.

• There is a very small step in the body of the tube, just forward of the front mount arm (also just forward of the Colt logo) unlike the 4x21 which is smooth.

• The elevation adjustment cap is the small piece on the very top of the range selection knob.  In these pics, the range selection knob is knurled, but the cap on top is not. On mine, both the the range selection knob and the elevation adjustment cap are knurled.

• The top of the elevation adjustment cap features a "half-moon" slot, not a straight slot.

Mounting bracket side view

Mounting bracket bottom view

Earlier inspection sticker: oval silver sticker;

 Later sticker round yellow

   

Comparison of elevation and windage dials on the 3x20 and 4x20

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Colt 4x20 marked 'Made in Japan'

with original Colt marked paper