When Handgun Matalic silohette shooting started in the area I lived I played with service style pistols at 50, 100, 150, and 200 meters, using a Browning HP and my Colt Gold Cup.
The limiting factor was my ability to hit these targets at those ranges. But when I did, the 45 faired better, or should I say I had better luck knocking over the targets with the 45.
For me the 45 was more accurate, but I think that had a lot to do with I'd shot the Cold Cup in Bullseye matches and was more use to it.
But like I said, this is a poor example, I wasn't that hot shooting semis at extended ranges. 357 & 44 Mags worked better for me, or better yet, on of my TC barrels.
Best advice I can come up with is barrow one of each and see which one you shoot the best at extended ranges. You can deside which one with a 5 inch barrel you can shoot the best, then with the 16 incher, you'll be that much better.