This article reports on the results of an exploratory phenomenological study of six Nebraska high school physics teachers and their perceived impact of participating in a collaborative scientific research program that provided training in experimental procedures and advanced, extracurricular physics topics, all building on fundamental high school physics concepts. In the context of this paper, subject matter expertise will refer to teachers' understanding and confidence in the subject as well as their view of self as a teacher, scientist, and physicist. A conclusion is drawn that through collaborative scientific research activities, secondary teachers who are teaching physics outside their primary field of training can build confidence in this particularly challenging subject area and achieve a progressive view of self not just as physics teachers but physics experts. This document suggests subject specific on-going teacher professional development opportunities may be crucial to helping physics teachers become physics experts.