Blazer was a model from Wolfram when he sold to S&W.
the 06 is for many guns. The Colt New Frontier 6" Peacemaker,
Great Westerns's 5.5", Hawe's Marshall 5.5" & 6", and many more.
There is a fit chart here on the forum:
1978 S&W Leather Catalog and Holster Fit Chart.
I think you have a holster that would be a prize for many
cowboy action types.
In Omnia Paratus