21 I must be drunk because I am about to advise you NOT to get a new gun unless thats just realy what you are wanting to do. For TN whitetail (and anyother whitetail this side of a 400# Kansas giant) the 06 is MORE than capable of taking them to 400yds if you are. The 180 is really just a hamper on deer and doesnt allow the cartridge to " stretch its legs" , save the 180s for elk and try something lighter. If you tried something like the 150 BTSP Hornady Light Mag (I assuming you have at least a 22" barrel and its a bolt gun), you would be EASILY prepared for any TN deer inside of 350 yds easily and farther if you are prepared and have enough scope. A 7mag is PERFECT, but for someone that already has a " standard deer gun" (25-06-30/06) there just isnt enough difference IMO. I personally think you need to go up to at least a 300 RUM to notice any appreciable difference over what you' ve got now. And dont write off the 243 either. With the right loads and a keen triggerfinger, I' ve seen 243s DUMP deer at 300+ yds when hit in the neck. For broadside shots, I would keep the 243 under 250. In the hands of a competent triggerman, both loaded fast and light, the 06 and 7mag are no different inside of 400yds. 150 Ballistic Tip Federal Premiums are a great 06 load as well.
Did I just say that? [
LOL just remember you got that advice from a man who shoots a Warbird at TN whitetails. But I had over 10 years and probably 75+ dead deer stories with an old 30-06 (and many years and probably over 20 deer with a 7mag likewise). If your gonna switch make it a BIG switch!