ok first I would slug the bore and check the chamber(if you haven't already) to make sure it's still chambered for 7.35. these guns get a bad rap for being POS but that group seems a little out of the ordinary.
2nd, I'd make sure that your LGS was actually loading .299 diameter bullets and not cramming .308 diameter bullets down a .299 bore. the opposite may also be true, your bore may oversized and may be better suited to loading .308 bullets rather than .299.
3rd, I'd pick the brains over at the reloading forums here, as well as check and see if there is anything in the italian forums at milsurps.com. good knowledge base over there with those guys, they may have found some loads that work great.
ignore my complete lack of capitalization. I still have no problem correcting your grammar.
I never said half the stuff people said I did-Albert Einstein
You can't believe everything you read on the internet-Benjamin Franklin