Colt 3X & 4X AR15 Scopes


The colt 3×20 and 4x 20 scopes have been around a long time.  Almost as long as the AR15 it was meant for.   It is one of the first optics to ever be designed specifically for the AR15/M16 and was  used during the Vietnam war.

The optic attaches to the carry handle of the upper by using the hole in the center.   A threaded post protrudes out the bottom  and a lever is used to tighten the assembly to the underside securing it tightly into 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 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. ll 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 BDC does match and work pretty well and it is repeatable on  all of the examples I have tried over the years.  The optic is calibrated for the M193  military load which is the 55 grain bullet.  At the time there wasn’t much else out there.  Even later models  can safely assumed to be matched for the M193 type load.

The crosshairs for the scopes came as a  post of a duplex crosshair. I have never been much of a post fan myself.  The glass is very clear on these optics. Of course you can find some that have been used and abused and see  some narfed up glass.    They are not ACOGs, so they can not take that kind of abuse. But that isn’t  to say they are delicate.  They did see actual combat use from Vietnam to the first Gulf War.

Except for a few  very early makes, the Colt optic is usually marked Made In Japan.   The 4x model is the same size as the 3x.

Other than the older models having a slightly shinier finish than the newer made ones, the y are nearly identical.

Like all carryhandle mounted scopes, there is the  usual  issue with cheek weld.  It is something a cheek rest could remedy,  but why bother.   I think the days of this being  your only choice for an optic for your AR/M16  may be over.    Now they are  too collectible and slightly rare to be out using for much more than fun anyways.  And they are a lot of fun to play with. Or even hunt  deer with.   3x and 4x are still usable and hunters and snipers of years and wars past used scopes not even as powerful as 3x for serious work.  They can be used for some pretty decent precise  shooting in  reasonable conditions.

The copes came in a cardboard box with  leather end caps to protect the glass.  Inside was simple instructions on how to zero and use and take care of the optic.

The little scopes are a neat little piece of AR15 history and they are a lot of fun to shoot with. Especially on an older SP1 rifle or M16 clone.   If you have ever wanted to hunt with your old SP1 or clone and  iron sights won’t cut it for you these are just the thing  for getting some real use out of the old retro AR15.


      • Wouldn’t an A4 detachable carry handle since they’re essentially identical to the A2 handle and the scope fits on that?
        Speaking of which, I was wondering if an A1 carry handle would fit an ACOG in a direct mount. Might be a good idea for a short blogpost to get the SP1 out and check if the acog fits 😉

        • yes, it will work on the carry A4/M4 handle and yes an ACOG will mount to a M16A1/SP1 carry handle. Also, I like to think this website stopped being a blog a long time ago. I think the site and community of readers and commenters outgrew that several years ago.

          • I’m simply too used to Hognose’s terminology, may he rest in peace. Who am I kidding, he’s probably doing cartwheels in his grave. Until the very end he went “blog this”, “Your Humble Blogger that” and this site is not up to the number of insightful commenters of Weaponsman yet. Oh, the irony is not lost on me. I know I’m not adding much to the discourse myself, but it’s 2021, everyone deserves a gold star for participation 😉

          • the site did start out as a blog but its grown beyond that. There is sometimes some negative connatation that comes with “gun blog” now a days as well that irks me depending on who is saying i. Not you, but some of the slick rag shills say “gun blog” is a dismissive, pretentious manner meant to write off anyone not part of the old gun media boys club. Never mind more people read looseRounds than read Gun & Ammo, its just their coping with being part of a dying media

  1. I bought one of those used, a 3x, when I was a kid back in the 80’s. I think I paid $200 for it, which was no small amount back then making just over minimum wage (minimum was $3.35 an hour back then in California). I always wonder what happened to it. Probably rusting away in a box somewhere in my storage shed. I remember some company in Shotgun News called Keng’s Firearm Supply that used to sell Chinese knockoff’s of the same scope for 30 or 40 bucks.

    I’ve wondered whether or not that scope would fit on a flat top detachable carry handle, but never tried it. Your article made me look up those old scopes and I noticed Brownells sells a Reproduction version for $400. Wonder if its made by Hakko of Japan like the originals or if it’s a Chinese factory manufacture?


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