I read that Unique burns in a similar manner as black. I am not sure about using slow burn powders with light shot charges in Damascus barrels. Many old quality guns had their barrels "swamped" in a severe manner. That means they got thin quick! A powder like Red Dot will propel a 1 oz charge below 7000 psi and it will be consumed before the wall thins. 7625 will hold pressure out a foot or so.

bill