Here are some:
http://www.gunengraverdwharris.com/

http://www.terrytartist.com/

Paula Bieson is great for animals or anything but isn't taking new work for a couple of months. http://biesen.com/Engraving_2.html

Tommy Kay wasn't listed I am not sure if he is still around. There is also a Gun Engravers guild which has a directory that might help.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli