I have both, and have shot (and hunted) with both. Wayne (AHR) built and tuned my .500 J. Feeds, shoots, behaves like a gem. Lon Paul, tuned, trimmed, customized my .505 Gibbs- and it shoots, feeds, behaves the same. Guns both weight 11+ pounds, and both at 2200 fps, 525 gr bullets, the .500J a...