Trajectory deflections of 5.56 NATO and 7.62×39mm rifle bullets, fired through 7.5, 15 and 22.5cm of gelatine, were studied. The magnitude of the deflections from the bullets' original trajectories after perforation are related to the length and the profile of the (wound) channels through gelatine. After 7.5cm of penetration depth, deflection was less than 1°. With the longer channel lengths, bullet instability set in and subsequently, deflection was much larger. Deflection was highest with fragmented 5.56 NATO bullets after perforating 22.5cm of gelatine. The data from this study can be used to assess the degree of bullet deflection in trajectory reconstructions after incidents where human bodies were perforated with rifle bullets of the respective calibres and cartridge types.