 The new design improved overall ballistic protection by eliminating the "hatchways", while also allowing for larger hatches for the driver and bow gunner.The cast hull M4A1 for the most part retained its previous glacis shape even after the larger hatches were introduced; the casting, irrespective of the larger hatches, sat 37 to 55 degrees from the vertical, with the large majority of the piece sitting closer to a 55 degree angle.The transmission housing was rounded, made of three cast sections bolted together or cast as one piece.