I think that you are asking how to unload the shotgun. I don't believe that the magazine can easily be removed. You will have to "cycle the action" to empty the gun.
In a safe area with the gun pointed in a safe direction, you will pull back on the lever that sticks out of the right side of the gun and eject the UNFIRED shell. Let go of the lever so that the action closes and a fresh round is chambered. Pull back on the lever again to eject the fresh round. Repeat as many times as necessary to empty the gun. Keep you finger away from the trigger (which is the small lever inside the metal circle sticking straight down).
The magazine holds two shells.
Need model number
http://www.histandard.info/manuals/sears/pashotguns/index.html
Winchester
The Sears Ted Williams Model 300, semi-auto, shotguns were made by Winchester. The Sears 300 is the same as the Winchester Model 1400.
50-150 USD
100-300 USD
50-300 usd
100-260 US Dollars
Winchester, same as model 1400.
We have them. gunshop@nctv.com
200.00 to 350.00 depending on condition.