In large mixing bowl, toss together sugar, tapioca, blueberries and juice.
Roll out pastry bottom on a well-floured surface to fit in pie dish. Place in the bottom of a 9 1/2-inch deep-dish pie plate. Spoon filling into the pastry shell.
Chill while rolling out top layer of pastry. Cut out 5 or 6 small holes in pastry top using a decorative cookie cutter. Gently roll dough onto top of pie. Crimp edges of pastry to form a tight seal and decorative trim. Brush pie with egg and milk wash.
Bake pie on a tray for 45 to 50 minutes. The blueberry filling should be bubbly and the crust golden brown.