I've been playing, trying to complete all the random challenges the game offers up for minor xp bonuses or perks. After running out of 12 gauge ammo for my Hunting Shotgun, I switched over to my Sturdy Caravan Shotgun. About 150 rounds later I checked my progress and found that I was at the same place I was before. This weapon does not register in the game as a "shotgun", though it was still giving me credit for rifle grip weapons. Hopefully, they can fix this in a future patch