# Colt 3x20 scope on AR-15 rifle



## smeth

I have a Colt AR-15 target rifle with a Colt 3x20 scope. I don't have any instructions for the scope and would like to know what one of the adjustment screws, in fact, adjusts. It is on the right side of the scope and is the only adjustment with a screw-on cover. The adjustment itself uses a slot screwdriver to change it. Could someone tell me what this adjusts? Thanks in advance.


----------



## DJ Niner

The right-side adjustment turret is for windage (left/right adjustment). There should be a little arrow and an "R" or "L" indicating if you turn the slotted adjustment screw in that direction, the bullet's impact on target will move Right or Left (I don't remember which is used; it's been a few decades since I owned a similar scope, but I don't think they've changed the basic design, so these instructions should still be correct). If there is no direction indicated on the dial itself, look inside the cap/cover for a sticker with this info.

The top turret is adjustable in the same manner, but you have to remove the cap/cover located in the top of the large adjustment knob itself (this knob is used for bullet drop compensation). If I remember right, I think this cap/cover is slotted so that you can use the rim of a fired casing to remove it. To zero the scope, remove both adjustment covers, set the Bullet Compensator Knob to the distance you are shooting (100 yards, 200 yards, etc.), and fire a 3 to 5 shot group from a steady rested position. Find the center of the group, and move the windage and elevation screws in the appropriate direction to get the next group of shots closer to the center of the target. When adjusting the elevation, hold the larger/outside Bullet Compensator Knob on the same setting (100 yards), and only turn the INSIDE dial. Shoot again, check the group location. Repeat as necessary until the shots are grouping in or around the target's center. 

Don't forget to replace the scope covers/caps when you are done. I see these left on the shooting benches quite regularly, and I always get sad when I see them, knowing someone is gonna be pissed when they later find out they left them at the range (way out of town, and a REALLY long drive for some folks).

Good luck, and good shooting!


----------



## Billkhere

What is the slotted cover on the left side of the scope for ? Thanks


----------

