I have owned at least a half dozen 243's in my day. In that time I've yet to find one that wouldn't shoot the Federal Premium 100 gr. Nosler Partition pretty well. I once had an old Mossberg bolt action that would put them nearly through the same hole. So, I went back to the local shop and bought the last 8 boxes he had from that lot #.

I will agree with the others in saying factory ammo of any form is much better than it was even 10 years ago. If you have the time and money I would start with the load above and if it doesn't meet your accuracty requirement try another brand but for deer I would stay in the 95-100 gr bullet weight.