aakk9999 - 1:26 am on Jul 8, 2012 (gmt 0)
And then I deleted the 301s as soon as I saw the old URLs weren't getting more than a handful of hits, and the new ones had "taken" in SEs and social media.
You said you did not check the backlinks to these pages. Have you removed 301 before your drop? What I am getting at - is it possilbe for the drop to be because of loss of linking juice because you have removed 301?