Marsh,
Actually there are severeal scopes that are legal for BPCR Silhouette. Navy Arms imported a brass tube scope for years that was and still is a legal scope, they may even still have some of these I am told. There are three Co's today that are making scopes for the new scope class of BPCR Silhouette they are MVA, RHO and Parsons. All of these are very good scopes and all are a little pricey, but the quality seems to be there. The rules on scopes say that it must be a 3/4" tube with no external adjustments for windage or elevation. Your Unertl may just qualify! Good Luck Gunny