I'm not 100% certain, but I'm sure someone will correct me if I'm wrong. If you look at the muscle in George's neck, you will see the front edge is visible on both varieties. However, the rearward edge is only really visible on the 'shallow' neck variety ie you should see a slight depression forming a line from just above the BM on the truncation towards the bottom of the hairline. Best explanation I've seen, Nick - good one! I've got 3 types of 1911 shilling to look out for, in my ever growing list: Obv 1 Rev A, Davies 1790: I of GEORGIVS and D of DEI between beads, hollow neck Obv 2 Rev A, Davies 1791 (commonest): I of GEORGIVS and D of DEI at a bead, hollow neck Obv 3 Rev A, Davies 1792 (scarcest): I of GEORGIVS and D of DEI at a bead, flat neck