I am quite sure you are going to be very happy with your new Super 14 .223. I have had several over the years (both 10" Bull Barrels and Super 14's, both Blued and Stainless) and in all of those there are a couple of things to note. 1st is with the 10"ers. As stated muzzle blast was fierce until I learned how to load for it (yes 40gr. Nosler Ballistic Tips loaded with IMR-4198 was the ticket). 2nd, of all the 14"ers I have had I had one that I couldn't get to shoot and sent it down the road.
I have used 40gr. Nosler Ballsitic Tips with IMR-4198, H-4198, H-322, W-748 and Benchmark all with good results and accuracy. I have also used the old 52gr. Speer Flat Base Hollow Point with either H-322 or W-748 with good results and accuracy. I had one particular 14" Stainless .223 that just loved 55gr. Nosler Ballistic Tips loaded with H-4895. 3 shot groups at 100 yards from a bipod would result in sub 1/2 MOA groups more times than not.
Good luck with the new Contender.
Larry