A good .22lr can shoot much better than 3inches on a fair day.
Ammo change isn't going to fix much.
Really? Its not uncommon for guns to like one kind of ammo better than another, to the degree fo 1-2MOA difference isn't uncommon, especiallly when dealing with a lightweight field rifle like the kimber hunter. Multiply that by shooters habits, optics setup, range conditions, etc. 3" from a perfectly fine gun isn't unreal and doesn't necessarily mean the gun is faulty. My adirondak will shoot 2.5-3" groups with 150 grain ammo, but with 165-168 gr. target and multiple brands of hunting ammo it will shoot 1" all day long if i do my part (mostly being patient and letting the barrel cool between shots) for a 6lb gun, scoped and loaded witha. Sling, thats not too bad...
The ejection issues are a concern though. Might be headspace issue causing brass to swell/stick, this would also explain accuracy issues, and If I were kimber I'd want to see it also. In fact I want the OP to send it to me to play with and see if I could diagnose it :]
