I have a book the Longriffles of Pennsylvania. By Russell Harriger. About the gun makers in Jefferson, Clarion and Elk counties. It is in out of print but can be found by searching the internet if you want a copy.
This book has a page on a family member named. Harrison (Harry) Hallowell born around 1843 according to census of 1880.
I can email the pages to anyone who would like them.