i have a 243 win and i need to upgrade. but to what?

What do you intend to do with with another rifle? Target shoot, varmint hunt, deer hunt, elk hunt? Every deer I ever shot out to 300 yards with a 243 died just as quick as any shot with any larger caliber rifle. If you put a 100 gr bullet where it is supposed to go from a 243 I will get the job done.

Is it for sale? I like 243's.

lol, Greg, me too. .243 is one of my favorite calibers.

To the OP, I would suggest a .308 or a .270. Fantastic all around cartridges

a .243 is just a necked down .308 casing, so you should be able to get the exact same rifle just in a different chambering so it will still be familiar.

Friend, My choice would be a 25-06. Very fast, and when you hit something - It stays down.
I personally have a Savage Tactical, and it is an outstanding weapon. Mate it with a Leopold fixed 12 power , and you can't beat it. The heavy barrel doesn't bother me a bit, as I got used to big iron in the service. the extra sling eye on the forearm for a bipod is a great feature.
I was hunting in Northern Wisconsin about 12 years ago, and hit a 220 lb buck square in the chest, and it went down like a sack of oats.

My brother on the other hand, prefers the big guns. He uses a .338 Ruger, that can kill with just the muzzle blast. Too much gun, I say.

I just believe that a 25-06 is very under rated, and will work well under all conditions, from varmints, to deer. Besides, I like fast bullets, and blowing ground hogs up.

I have hunted with a 30-30, 30-06, 270, .308, 300 WIN MAG, 7mm, .44mag and I final ended with the .243, so if you must have something else, I suggest trying the .308.

I like short action bolt rifles, so the .243, 7mm-08 and .308 are usually what I look for in deer rifles. Don't be confused, the .243 is not a kids or womans gun despite what some of your bucket headed buddies may tell you. It does not offer as much margin of error, so I don't blame you for looking at other rounds.

The .308 is a popular round. It is easy to buy a variety of ammo off the shelf and lots of guns are chambered in it. The recoil is more, but not so much that you could not get used to it with practice.

This is the most important question of all and one asked by a couple of folks already, why do you need another caliber? What need do you need to fill. Without that info it seems folks can just suggest till the cows come home for their favorites, but that won't necessarily serve you. If you need something bigger I wouldn't simply move up to a 270, that might not be sufficient. Please tell us more about your needs.

I will say this though, stick to rounds which are numerous and old school if you will, where you have many choices of gun and ammo.

These are the guns I pick up to take with me most of the time
204 Ruger
270 or 25-06
7 Rem Mag
416 Remington Mag

They will handle just about anything in the spectrum.

On lesser occasions I will pick up the 300 Mag and lesser often still the 30-06. If I am blowing away prairie rats then maybe the 223 since the ammo is much cheaper than the 204. Lately though I have preferred the 22-250 to the 223 for that. Others will have their favs as well, if you want to heed their advice make sure your needs are similar to what they do and need. For instance I have no use for a 30-30 at all. I don't own one and wouldn't go buy one, no need for it. But if you like the way they shoot and it fits your needs, check them out.

Also find what works well for the action you like to use. My lever guns are all in pistol calibers, a holdover from shooting cowboy stuff. My only semi-auto other than fun guns are 22's. I primarily like bolt action rifles and when I feel especially giddy, double guns. Overall though I am a bolt action kind of guy. And the choices out there for those is unbelievable.

The .243 will easily take down anything in Tennessee. If you were to buy another rifle I'd go 308 and be able to take anything in the country. The .270 would be just a stopping place until you move up to 308. The .243 is fun to shoot but the 308 reminds you that you are shooting a real rifle. I'm sort of prejudiced, I carried an M14 for 4 years.
Cherokee Slim

I think if I was to buy only one more rifle and I wanted something to take advantage of just about any hunting opportunity in NA I would look at 30-06, 7 rem mag or 300 mag.

A 308 will get just about anything here, though it is minimal for big bear at safe range, or elk and moose at long distances. People will tell you that you can always use heavier bullets but I have found heavier bullets in anything can be unpredictable in accuracy. Most rifles truth be told won't shoot everything accurately, most have some sort of favorite usually in the middle of their cartridge range somewhere. With the three above cartridges you can take just about anything, though a large bear is marginal at a long distance with those 3. With that exception you could shoot almost anything in N&S America, Europe and most plains game in Africa. To me they are the most versatile of the most well known cartridges.

This is the way I see it, if you get to by some odd chance hunt with someone for something very special that you may not ever get to hunt again, do you want to take a chance that the cartridge you own is marginal for what might be only a very long shot.

I err on the side of caution, but that's jut me. Then again you may feel you will never have a use for anything that big and then a 270 or 308 will suffice and the shooting will be cheaper. If you want a bigger rifle for possibilities then look hard at one of the ones I listed above. I have no real preferences to the ones listed above, I like the 7mm rem mag for its flat shooting, the 30-06 for its functionality and the fact that you get get ammo for it almost anywhere in the world and the 300 mag because I think it is a pretty good mix of power and recoil management.

I look forward to hearing what you are planning for if anything specifically.

I will agree with you Swamprunner. I have killed well over 200 deer in my life and I have killed them with about everything from an arrow through a 45-70 and there is not anything in my experience that will drop a deer in it's tracks consistently like a 25-06 with a 100 to 120 gr bullet. I like the 117 Sierra the best. I tell people that I quit using the big mags because I could not carry enough flash light batteries to track down a deer that was shot perfectly. It is BANG FLOP with the 25-06.