I use 3/4" pine that I select and assembled using strong halfblind dovetail glued joints .  I then router the exterior corners so you can easily install standard corner protectors if you so choice  . The front and back panels are 1/2" birch plywood .   All the cabinets I sell are sanded to #150 grit when they are mailed off to you the buyer . Comes predrilled with 1/4” hole so you can attach your chassis . Buyer must contact me if he wants the 1” hole for the sus4 installation hardware

18 9/16’’ wide x 9 1/2’’ tall x 10 1/4’’ deep

Chassis cutout is 17-1/16’’ x 2-9/16’

This cabinet will fit a 1989 vintage mark III and a mark IIC- and a mark IIC+ and a .50 caliber