There is only two left...
(Those should be illegal...)
Aluminum Chassis for Swiss K31 Rifles by Sureshot Armament Group
https://www.thefirearmblog.com/blog...ssis-swiss-k31-rifles-sureshot-armament-group
If you dislike the 'tactical wood'... this one will really spike your blood pressure:
There ya go, always a treat to see. Muzzle brake looks a lot like that for an FG-42, one of the more efficient designs. Bet it's a sweetie on the range.