Plenty of Atolls fired during air war over Nth Vietnam. No matter whose numbers you use, it must be agreed that the VPAF(VNAF) MiG-21 guerrilla/hit and run tactics were very good and they achieved very favourable kill ratios against the much larger and formidable USAF/USN over Nth Vietnam.
Of course the USAF in particular was hampered by poor strategy and tactics and the dreaded "ROE" dictated from the Whitehouse in particular. Had the USAF at wing level been allowed to use their own tactics and fight the war their own way, it's highly likely that the war could have been over in 1968 - Hanoi came very close to folding in 1967. The end result would have been the same with the eventual collapse of the South, but literally many hundreds of thousands of lives could have been saved. Imagine trying to fight a war and not being able to destroy the airbases, not shoot at a MiG until it takes off, not being able to hit a SAM site until it's operational - Lyndon Johnson and "Dr. Strange" McNamara have a lot to answer for.

This makes for some humbling reading - refer to the MiG-21 kills Vietnam War.
http://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-21