Rick Vasquez was the Assistant Branch Chief of the Technology Branch of BATFE. He has now retired and owns a firearms firm in Virginia. Before he retired from the BATFE, analysts under his management did the research and technical evaluation of the bump fire stocks submitted for approval. Rick reviewed their results and approved their evaluation. Moreover, he makes no apologies for it as it follows the law as written by Congress.
In the video below, Rick is interviewed for a Vice News/HBO report. While Vice TV often has a leftist slant, they played it straight on this one and let Rick explain things. He also shows the reporter how you can bump fire without a device or special stock.