Jeff sent a nice reply and recommended his compact case in either leather or canvas & leather. He also wrote what size would be best and other helpful info.

Size - 12ga 28" (block the last 2")
Use a leather patch or something in the lid where the express sights touch the material or the sights will tear the felt.
He has many customers that have used this case for a rifle.
Case dimensions are 31" x 8 1/4" x 3 1/2".
Green interior only.

The Ultimate Compact Gun Case
Canvas & Leather
12/16ga up to 28"
Model #C/LCAS1030.2
$189.95