In practical terms, the real reason why they wear gray is is a matter of happenstance. In fact, some Union troops wore gray during the Battle of Wilson's Creek on Aug. Union soldiers might be wearing gray - and not blue - early in the war, but not by the end of the war, says Connie Langum, the historian at the national park site, which is southwest of Springfield.

To pin down this down, I called the people who live and breathe this stuff over at Wilson's Creek National Battlefield.

Historically, Wlezian says, Union soldiers occasionally wore gray uniforms. The intent of Bass Pro owner Johnny Morris was to have the re-enactors represent Civil War soldiers - not necessarily Confederate or Union, says Jack Wlezien, director of communications for Bass Pro.