I've only been around 2, a .308 and a .222. Both shot excellent.
I would check the normal things first, proper stress free assembly and bedding. Then check scope and mounts. With a good load and straight ammo, and those 2 boxes checked, I can't see it not shooting 1" or better. How's the trigger? And what optics/ammo are you using?
I'm not sure what a gunsmith could do besides the above, unless you're talking about rebarreling or something of that nature.
