More from the "M" box; a trio of M & B Mining, Inc. ingots from Las Vegas, NV. In the first photo, the three variations that I have seen in the 5 oz class over the years are represented. I have read in a number of places that the first hallmark was used prior to 1969 when the "double lined" hallmark was filed as the official trademark. I could find nothing on how long before 1969 M & B Mining, Inc. was in business but public records show closure in 1974. The hallmark is commonly referred to as "Omega" but the trademark filing indicated it is a fancy M & B intertwined.
I am being very specific about only having read this information, anyone have something different to add please do.
The group of ingots on the same castings keeps adding up. Note the two varieties of weight and fineness stamping throughout the examples below: Coin Shack; Doyle's Mint, Riverside Coin & Gold, (RCG); M & B Mining, Inc.; MSC; and Nevada Coin Mart, (NCM).
And finally a new name for the week, MRI just acquired. An older looking cast ingot with apparent machined obverse.