shortwave - Davidson's is a large gun wholesaler that sometimes commissions (I think that's the right word) special runs of particular models from manufacturers such as S&W. They typically specify that the guns be made with certain features (e.g., special barrel lengths, porting) that may not be available on the standard factory runs. These guns usually sell for a premium due to these special features. Lew Horton is another wholesaler who does the same thing. You can Google either of them to learn more.