[GreenKeys] Determining the age of a Model 15-KSR

[Jim Haynes]

Wish I could help, but I don't know any more than the rest of you.

In addition to the factors John mentions, there was all the cast iron
early on, replaced later by aluminum.  I don't know if both materials
were used at the same time.  Some units made for the Army in WW-II are
cast iron - maybe aluminum was in short supply.  Maybe aluminum castings
imply post WW-II, but I don't know that aluminum was not used earlier.

jhhaynes at earthlink dot net