6.5x55 is a .264" diameter bullet x 55 mm long case. .308 is the 7.62 x 51 NATO. I am not sure that there is a good selection of varmint bullets for the 6.5 diameter. I would look at the light Nosler BT's and the Barnes X. I think Sierra makes some light bullets for varmints and/or target practice that should fill the bill. Not sure about Hornady. Speer only makes a 120, and 140 grain softpoint.

http://www.sierrabullets.com/index.c...ts&caliberID=6