Recently able to add yet another 40 oz class U.S. Assay Office New York silver ingot to my collection, the 1951 example third from left. These are awesome ingots to handle, like a small silver brick; surprisingly heavy for the size.
Updated from my last U.S. Assay Office New York post, the 40 oz class silver ingots that I have come across in my research, represent the widest range of dates in any of the three common sizes; 40 oz, 100 oz and 1,000 oz. In the 40 oz class, I have now come across the following dates; 1908, 1928, 1940, 1946, 1949, 1951, 1952, 1954 and 1957. The examples pictured below are dated 1928, 1949, 1951 and 1957; four of the nine dates are covered so far.
Another neat thing about the 1951 ingot is finding a U.S. Assay Office New York silver ingot that is exactly as old as I am!