I have a SB speciality trap gun with a pull-release trigger. I'm looking for more information on this particular trigger type. I've looked in Brophy's spec book and found no mention of it. Any information would be most appreciated. Thank you

Glenn: it is unlikely that the release was installed by Hunter Arms, and it would need to be removed and examined to ID the maker.
No better release trigger guy out there than http://www.phillipsgunsmithing.com/

Thanks Drew. I kinda thought the same thing. I've never seen a release trigger that can be switched back and forth from release to pull. It seem to work and it kind of unique how it works. on release the seer is let go, but the hammer is held back until the trigger is released. Switch the lever behind the trigger to pull and it operates like a normal pull trigger. Thanks for the link I'm going to check it out.