Awhile back the question was asked on this forum, "What was the most victories (by a pilot) in one sortie?". And although the prize goes to the number 13, by German pilot Erich Rudorffer who downed 13 Russian aircraft in 17 minutes, the number 7 seems to come up alot.
For instance, a month earlier Rudorffer managed to down 7 Russian aircraft in just 7 minutes!
During the Battle of Santa Cruz, on October 26th, 1942, U.S. Navy pilot Lt. Stanley "Swede" Vejtasa downed 7 Japanese Naval aircraft (2 D3A "Vals" and 5 B5N "Kates") while flying top cover over Task Force 61 in a F4F-4.
Major Bill Leverette downed 7 Ju-87s over the Isle of Rhodes while flying a P-38G on October 9th, 1943.
And Capt. William Shomo downed 7 Japanese aircraft (1 G4M "Betty" and 6 Ki-61 "Tonys") over the island of Luzon on January 11th, 1945 while flying a F-6D (photo-recon version of the P-51D).
Certainly the number 7, while lucky for these pilots, was not so for their enemies!!