My highest percentage was 54% with Red Death, which was my main go-to weapon for months and months before its damage was nerfed in favor of marginally-faster firing speed. It's also the reason that Pulse Rifles are still my highest amount of kills in Crucible (1900+) ... but, honestly the ratios are a bit skewed here. Stuff like shanks, minotaurs, and things with shields will just chip away at the percentage over time. Think about how many shielded minotaurs players who regularly raided VoG on hardmode must have taken down week after week. Now also think about how many rounds players have frantically shot into the Oversoul on Crota's End. :P