In regards to the T/C Contender Super 14 in .223, it is probably one of my most favorite Varmint Handgun Cartridges. I bought my first T/C Contender Super 14 .223 Handgun in 1982, and have had several since then. I have topped them with the 7x Burris Intermediate Eye Relief Scopes, the 2.5x7x Burris LER Handgun Scope, 3x9x Burris LER Handgun Scopes and the 3x12x Burris LER Handgun Scopes.
With the proper ammo, the right scope and a solid rest these handguns are capable of some amazing accuracy. I have shot Prairie Dogs at an honest 1/4 mile (yes 440 yards) with a T/C Contender Super 14 in .223. No you don't do this on the first shot or every shot for that matter, but with the help of someone spotting your shots you can walk em in. Yes these handguns (again with the right ammo, scope and rest) are capable of that kind of accuracy.
I am quite sure you will enjoy your Super 14 T/C Contender in .223 if you are into handguns and shooting handguns.
In regards to the 7-30 Waters, I used this cartridge in a 10" T/C Contender a few years back. I was shooting 120gr. Nosler Ballistic Tips loaded with Winchester W-748 Powder in Federal Brass. Accuracy was consistantly between 1" to 1 1/4" for 5 shots from the bench at 100 yards.
I was fortunate enough to take 3 Whitetails with the 7-30 Waters and a buddy took a nice Whitetail Buck with it also. Every single Whitetail we shot with the 7-30 Waters - 120gr. Nosler Ballistic Tip was a one shot kill. The one 4x4 Buck I shot and a Button Buck I shot were DRT and never ttook a step. The Whitetail Doe I shot ran about 30 yards (in a circle before collapsing and the Buck my buddy shot rran about 30 yards before collapsing. None of the 4 required a second or even finishing shot.
Last year I used a borrowed 15" T/C Encore in .243 Winchester with an 80gr. Speer Hot Core Spitzer to take two Whitetails on January 1st at slightly more than 200 yards each. I am currently trying to purchase this Encore I borrowed. Yep these things really get in your blood.
Good luck with the Contenders but be WARNED these things are ADDICTING.
Larry