Stir in milk, sugar, shortening, salt, and 4 cups of flour. Beat with electric mixer til smooth. Mix in enough remaining flour to make dough easy to handle.
Turn dough onto lightly floured surface. Knead until smooth & elastic, about 10 minutes.
Place in greased bowl. Turn greased side up and place in warm area until double in size. Test dough by pushing 2 fingers into the dough about 1 inch. Dough is ready when finger marks stay.
Divide in half and roll dough into a rectangle about 8 x 12 inches. Beginning on long side, roll dough snugly into a roll. Pinch edge of dough to seal and fold ends under. Place loaves seam side down in greased loaf pans and let rise til double.
Preheat oven to 325. Bake until golden brown and sounds hollow when thumped, about 40 minutes.
Remove from pans immediately, brush top with margarine and cool on wire racks.