G&G GR16 R4 Commando
 

I just got this AEG, and I can't seem to remove the rear sight. The knob that is supposed to turn won't budge at all. I've tried both clockwise and counter-clockwise. Can anyone help?

Should be counter-clockwise. Probably just really tight.

Thanks for the advice Saint - I got it to turn by using one of those rubber can-opener tools I found in my kitchen.

Another way to do it would be to wrap a wide rubber band a couple times around knob for better grip. Less likely to scratch something that way.