Lift the bolt handle, pull the bolt to the rear. Depress the trigger and hold it to the rear and you will be able to remove the bolt. Unscrew the takedown screw (large screw visible on the bottom of the stock) and you will be able to separate the stock and barrelled action.
That's as far as you need to go.
sales@countrygunsmith.net
Glenfield,which was made by Marlin Firearms Company made a bolt action .410ga shotgun from 1956-1965.This was the marlin model 59 which is the same shotgun as your Glenfield model 60.
Your serial number indicates that your Glenfield model 20 bolt action was made in the year 1980.
$100
1932-1957
1978.
$25 to $125, depending on model and CONDITION.
About 100 USD.
Go to Cheaperthandirt.com
Open the action and fire it while pulling the bolt toward you as if you were aiming the gun.
Lift the bolt handle, pull the bolt to the rear. Depress the trigger and hold it to the rear and you will be able to remove the bolt. Unscrew the takedown screw (large screw visible on the bottom of the stock) and you will be able to separate the stock and barrelled action. That's as far as you need to go. sales@countrygunsmith.net
About $150.00
$130 if in perfect condition