Frame 313

At a measured camera rate of 18.3 frames per second, frame 313 falls roughly 5.6 seconds after the presidential limousine turned onto Elm Street from Houston. The frame shows a spray of skull and brain matter emerging from the right side of President Kennedy's head, with Jacqueline Kennedy turned toward her husband. The following frame, Z-314, shows the President's head snapping sharply backward and to the left — the motion at the center of a half-century of ballistics debate.

The FBI's 1964 laboratory measurement of Zapruder's specific Bell & Howell Zoomatic set the running speed at 18.3 fps, the figure the Warren Commission and every subsequent inquiry adopted for time-motion analysis (Warren Commission Hearings, vol. XVIII, CE 884).

Life magazine acquired print rights to the film on November 23, 1963 and full rights on November 25 for $150,000 (Stolley, Esquire, 1973). Life published individual frames in stills but declined to release motion footage. Frame 313 in particular was reproduced only in heavily cropped or blurred form until March 6, 1975, when Robert Groden and Dick Gregory arranged the first national broadcast of the full film on Geraldo Rivera's Good Night America — an event widely credited with catalyzing the formation of the House Select Committee on Assassinations two years later.

The HSCA's Photographic Evidence Panel, led by Calvin McCamy and drawing on twenty-two independent experts, examined the camera-original and first-generation copies frame by frame. On frame 313 specifically, the panel concluded that the visible debris cloud is consistent with a shot entering the rear of the skull, that no evidence of alteration is present in the frame, and that the film runs at 18.3 fps without interruption from Z-133 through Z-486 (HSCA Final Report, vol. 6).

The panel's conclusion on shot direction was contested at the time by dissenting panelists and has been re-litigated since. The Committee's overall finding — that a shot from the front was "probable" on acoustic grounds but not photographically demonstrable — remains the last formal government position on the matter.

The rearward motion of the President's head from Z-313 to Z-315 has been read three ways in the peer-cited literature:

• Neuromuscular reaction to a rear-entry shot.Advanced by Luis Alvarez in 1976 using a "jet effect" model and adopted by the Warren Commission's defenders. See Alvarez, American Journal of Physics 44 (1976): 813.
• Impact from the front right (grassy knoll direction).Argued in Josiah Thompson's Six Seconds in Dallas (1967) and revisited with new acoustic analysis in his Last Second in Dallas (University Press of Kansas, 2021).
• Two near-simultaneous shots. The synthesis Thompson now advances: a rear shot at Z-313 followed within a fifth of a second by a front-right shot producing the observed head snap.

No forensic consensus has emerged. What is not in serious dispute: the frame is authentic, the frame rate is 18.3 fps, and the head motion in Z-314 and Z-315 is real and not a projection artifact.

High-resolution scans of frame 313 and every other frame are held by the National Archives and are viewable in the JFK Assassination Records Collection (NARA). Copyright to the images rests with the Sixth Floor Museum at Dealey Plaza, which licenses reproduction for editorial and scholarly use.

Continue to the frame-by-frame breakdown of the full 26.6-second sequence, or back to Analyses.