The Casio calculator I use is a 10 digit model so when I punch in Pi I am working to 9 decimal places. The figure I use which relates to the lead density of 11.365 grams per cubic centimeter corresponds with the cited '68 Gunbarrel Act chart in all 50 gauges 1-50 plus the additional 16 from 51.05 (.450")- 172.28 (.300") in .010" increments to the nearest .001". This is heavier than I have ever seen the density of lead given & would think it unlikely they had any adultrated with a "heavier" constituent. This is however heavier than I have ever seen given for the density of lead. Two possibilities come to mind
#1 They simply mis-measured the volume of their "Standard".
#2 It was suggested by another member, but don't recall now to give credit, that perhaps they used some method of bring the Standard to roundness which resulted in a slight compression of the lead leading to a smaller dia. This sounded very plausible to me.
At any rate & especially considering all their calculations involving cube roots etc had to be carried out by hand, their math was Simply Stellar.
