Thanks TT66. If you find out more, please let me know.
I asked an old time bullseye shooter in SE Michigan who shot along side of Reeves at various matches and he thought that Pfeiffer may have been located in Michigan, but was pretty foggy on it. We shall see.

I just read a post I had on the SWCA site and one of the experts said that Joe Pfeiffer was a gun smith in California in the 40s and 50s.