You must unscrew the muzzle cap and then remove the site locking ring. When you look at the muzzle you’ll notice it has a stamped sheet metal washer type ring behind the muzzle cap. There is a pin attached to it that goes into the front site post and secures the front site. After it’s removed you can simply remove the adjusting screw and remove the site.
Alternatively, you can switch the rear site to a different mode by removing the hand hard and pulling out the little pin that holds the adjustment knob on. Remove the knob and then remove the little part that shows the number (x100) of meters the rear site is set at. Turn it 180 degrees and reinstall. Originally all rifles are set to pointed bullets (100-700 meters). Flipping that part sets it to the round nose bullet settings (100-600 meters)