I don't really have a favorite caliber. Have used a 308 more than anything but because of the rifle, a mod 660 Remington, son has it now. Have used a 243, 25-06, 6.5x55 7x57, 7mm Rem mag, 338 win Mag, 6.5x06 and few others. Thing I found out was every one of them with a properly placed bullet kills deer pretty dead. Like my 6.5x55 and recently got a Mod 700 rebarreled to 260 Remington I think I'm gonna like. Though about a 250-3000 real hard but finding components was difficult and suggestions for making brass was all over the place, gave up and went 260 without regrets. One of the thing's I did like about my 308 was fairly low recoil, I hate recoil and it only get's worse as I get older. The mod 660 the 308 was in was an old fence post that handled and shot great! Cartridge I never used was a 30-06 although one did become my elk rifle. I think the problem was the first one I had had really bad recoil. Got rid of it and never looked back.If there is a best deer cartridge I'd call it either a 25cal or 6.5 cal on the 308 case or the 250-3000! Idea is bringing down recoil in a handy rifle. Weather cooled enough the other day to try out my new 260 and really nice for me to shoot! Working on it around 129/130gr bullets. Preferably Hornady spire points! Wish Speer made a 130gr hot core, I'd try them! Don't need a 120gr bullet, have a 25-06 that works fine with a 117gr bullet!