I don't know about 22-250 case life but my .223 hot loads are having a good case life. My test load brass has been used about 5-6 times and still looks like it is in good condition. That is one reason I chose the .223 over the 22-250 100 pieces of new winchester brass is only $13 and I can load a 40gr bullet up to 3800-3900 fps and a 55-60gr bullet up to 3000-3100 fps. I want to try the 53gr TSX bullets also but the 45gr XLCs did not shoot very well in my rifle. The majority of my shooting is with 40-45gr bullets so I am not loosing much velocity over factory 22-250s.

If I was going to use the .243 for deer I would use the 85gr TSX, I think it would be a good light recoil deer gun.

Good luck