I have just acquired a .243 rifle that I am going to be using this year. I have been reading that the .243 is "barely adequate" for deer
Somebody is blowing smoke up some where. Sounds like a statement from someone trying to sell some super duper magnum.
The 243 is an excellent deer round. Thousands upon thousands of deer have been taken with a 243. One of the most popular deer rounds in the west where we tend to shoot a little further the those back east.
Personnally I don't use one, I shoot a 257 Roberts, dern near the same thing. My wife uses a 243, and its never failed her. We use the same size bullets. Her 243 is a bit more accurate then my 257, but both are more then capable rounds.
If I didn't have a 257,(I really like my Model 70 Featherweight) the 243 would be my number one choice for deer and antilope size animals.
If I was to start over and replace my rifles, the first one I'd get would be a new FN Model 70 Featherweight in 243. Followed by the same thing in 270 Win for elk size animals.