First off there is no perfect Grouse gun. Ok now that thats cleared up it depends on the time of the season. Early on when the leaves are thick I like a DHE 20 straight grip and choked cyl/cyl. Early October when the Woodcock are available a VHE 28 also straight grip choked skt/skt sees the coverts. This year a certain AA 28 w/ball grip will make it's debut
When the leaves begin to fall and visability increases then the 28 inch damascuss GH 16 comes out to play with the ic/m chokes.
In reality the perfect Grouse gun is the one I'm carrying at the time I'm hunting Mr. Grouse
