W.H. Davenport died in 1904. H&A took over W.H. Davenport around 1901 and continued to mfg guns with the Davenport name until 1909-10. Per Dave: (http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=156069)
Do we know from whom the widow Johnson purchased the patents for the IJ gun?
Does anyone here have a schematic or pictures of the inner workings of the Iver Johnson variant? I have pics of the W.H. Davenport and the H&A.

John