I have some dimensions which differ somewhat from these,rspecially in the 12ga, but will have to get my book out tommorow. They are found in Roy Dunlap's book "Gunsmithing" from the 50's-60's. He doesn't state his source, I always assumed they were SAAMI for the time, but couldn't guarantee it.
Interesting to note the if you take the choke diameters in relation to the lengths they all form a straight line. They could thus all be cut with the exact same reamer by adjusting the depth of cut, at least for the 12, haven't checked the other gauges.
I also note full choke constriction is .036" for both 10 & 12 Ga's, .026" for 16 & 20 Ga's & .020" for 28ga & .410
