IME, you're not likely to notice cold welding unless you decide to pull some bullets. I have pulled bullets from rounds that had cold welded, but none of them from the same lot showed any signs of high pressure or split necks when fired.
+1
I've fired some old 30-06 and 270 from the '50s that seemed normal. When I decided to pull some bullets to use more accurate ones, I had to push them in with a seating die first or the collet just slid off. Some of the 270 made an audible "pop" when I pushed them in a hair. I don't think I'd have gotten any out with one of those plastic hammer inertial type pullers.
