What year is the rifle, got any pictures of it, so we can determine if it's a good model or not... Some of the older models were not necessarily known for their accuracy.
Handloading for it will be your best bet, no matter what model it is. Factory rifles are not necessarily coinciding with particular brands of factory ammo. It's usually a complete crap-shoot, and you will have to just try what you can till you find what works best. This can be a very expensive and time-consuming process. Most people who are gunning for the most accuracy they can, will handload for their rifle.