That's very interesting. Don't recall which loading manual I read it in, but I seem to recall reading in one of the major manuals that crimping rounds after seating the bullet gave each round a more consistent starting point, which in turn tended to develop a more consistent pressure from round to round compared to relying on neck tension only, resulting in greater accuracy overall. Might be worth comparing crimped with non-crimped in groups of 10 rounds each, and running them over a chronograph while doing accuracy testing.