That is very tough to do. Almost all bullets are the wrong shape but maybe Berger makes a VLD hunting bullet?
You can all understand the problem a bit better than I can explain if you read this post on another site:
http://theswissriflesdotcommessagebo...-#.VCN7lRY0fVZ
PRVI also sells bullets separately. The hunting bullet specifically designed for the Swiss K31 rifle is # B-428 (.308, SP, 174gr)