Chuck;
All I can tell you is "Do The Math". Any chamber cut with a cone angle of 5 per side is going to be a short one. It will not be a "Modern Long Cone", period. In my 35+ years in the machine shop I have cut enough angles & tapers to know how to calculate them.
I Double & Triple checked my trig, it is correct.
If you take the 1907 drawing Drew posted with the included taper of 1 7/8" per 12". Do the trig on this taper & you get 4 17' & 21 angle" per side. Calculating the length of cone for the .069" difference in chamber & bore diameters gives a length of .460".
Double checking by another means that .069" is 3.68% of 1.875.
3.68% times 12.5 = .460"
With that same .069" difference between chamber & bore a 5 angle per side would give a cone length of .394", certainly not a long cone.
Remember SAAMI is suggested Not Law.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra