Anton,
Thomas Woodward was also the inventer of the "Spiral Spring" action or known by his firm as "The Acme". His design was protected under patent #651 of 1876. These "striker" fired guns were well ahead of their time. Simple, innovative, and robust, yet extremely well made. Your Grandfather had many patents to his name. I've owned a couple of these T. Woodward Acme guns, I like them alot. :-)

Dustin