NC I seen where they offer an 85gr Partition for the 243. Have you ever thought bout trying that? Sounds like it could possibly give you the flat trajectory and the toughness for the closer shots.
As far as knowing my rifles I have killed deer with a pile of different guns and cartridges but the 270 with the plain ol cheap classic Fed 130's and the 7-08 with the 140 core lokts have worked about as good as anyone could ever ask for me. The 139 Hornady's and the 130 solid bases worked very very well in those 2 guns also....but Im too lazy to reload a lot

So if the factory ammo works that well I just keep using it. Both of those favored loads have killed deer from point blank to a shade over 300 for me.
The only load I have ever tried that absolutely would not group in the 270 was the 150 Speers.....probably 10 inch patterns..lol. Everything else groups well and shoots fairly simillar POI if I get in a hard spot and have to change ammo. The 7-08 shoots most anything I've tried close to the same POI except the NP's and they are inline but around 3 or 4 inches higher at 100.
Have you ever had to re-barrel that 243? I have heard it said they are barrel burners but I dont think I've ever seen one shot out. I know after 25 years my 243 groups as well as it ever did. Prob 1500 or sorounds through it.