I have the 1985 Gun Digest with that article, well read ......numerous times. Will have to look at my others as I remember there is an article about bore rifles in a '70's edition. I will post it similarly when I find it.

My W.J. Jeffery .577 3 1/4" ....... 1894 & proofed 3 1/4" & 6 1/2 Dram 650 bullet.
Baker did write that he preferred 6 Drams & 650 for better accuracy.
- Mike