Sterilize jars and lids in boiling water for at least 10 minutes.
Remove blossom and stem ends from gooseberries. Force berries through food mill. Measure 4 cups of the berry mash into a large pot. Stir in the sugar. Bring to a full rolling boil over high heat, and boil hard for 1 minute, stirring constantly. Remove from heat, and stir in pectin at once. Skim off any foam with a large metal spoon.
Take turns with skimming foam, and stirring the berry mixture for 5 minutes to let it cool slightly.
Ladle into hot sterile jars, leaving 1/4 inch headspace