a1 rear sight drum

Ive been trying to zero my ar with an a1 upper and the rear drum even with the detent pressed down it wont budge. Is the spring to strong, does it need some oil? any tips and help would be appreciated thank you

The A1 Rear sight is very simple, the only two springs are the small coil spring under the detent and a small leaf spring under the aperture for holding in the short range or the 500 Yd aperature, neither can get "too tight" to move the sight if you can depress the drum aperture detent and it springs back ( this was designed to use a 55gr 556 round to adjust with the bullet tip) front sight also for elevation.

without looking at the rifle my guess is it is bottomed out either left or right in windage making unable to move, or rusted frozen at the shaft aperture threads.

https://th.bing.com/th?id=OIP.4sV6OU...3&pid=3.1&rm=2

very easy to dissemble and clean, simply remove the very small roll pin (.062" ----1/16") in the exposed dial hub and thread the folding aperture from the shaft reassemble is in reverse.

thank you, I knew how to adjust it but ill take a look again with a more careful eye. I heard that people cut the spring down so there isnt too much tension to push the detent down or u wont be able to move it at al.

Disassemble it and see if their is any metal chips or debris in the spring hole in the carry handle this may prevent it from being depressed enough

Try to obtain an A1 REAR sight tool. Works so much better than a bullet. Note the there are tools for A1/A2 FRONT sights A1 has five prongs and A2 have four.

Attachment 165401

Steve