You may want to double check your trig.
This is a modern chamber/cone drawing. It typifies the modern cone considered to be longer than many early 20th century guns. As you can see, it has a 5* angle per side or 10* included angle cone. A 3* cone measured from either the barrel axis or normal to the barrel axis doesn't jive.
Chuck;
You were the one who said this drawing was a "modern cone considered to be longer than many early 20th century guns". In fact it is not a long cone at all. As I said I have double, triple now even quadruple checked my Math.
Yes a cone having an angle of 3°1' relative to the bore axis does indeed Jive. In fact to get the much vaunted 1˝" long cone the angle will be on the order of 1°20'12". This is based on a chamber .070" larger than the bore. Inv Tan .035/1.5 = 1.336658978°
As has been shown L C Smith was using a longer cone than this 5° one in 1907 & longer still by 1935.
