1365786 Measuring scatter of shot-gun pellets E HENRICHSEN 5 Oct 1972 [22 Nov 1971 14 Sept 1972] 46056/72 Heading G4H The scatter of buck-shot pellets is analysed by testing for holes successive areas of a target which has been shot at, the ratio of holes to tests for different regions of the target being displayed or printed out. In Fig. 3, the target is clamped on a transparent turntable (1) and scanned spirally by a radially displaceable photoelectric sensor 6, the detected holes being gated via AND gates 17 1 , 17 2 ... 17 n to counters 19 1 , 19 2 ... 19 n according to in which of n target sectors, defined by a clocking track and sensor 22, they lie. The frequency of testing (which may be such as to correspond to an area equal to that of a clay pigeon) is determined by an oscillator 11 the cycles of which are counted for the tests on each segment in counters 18 1 , 18 2 ... 18 n for division at 20 1 , 20 2 ... 20 n and print out at 21 once per revolution of the turntable. If it suffices to analyse only for complete annular regions, the clocking track may be omitted (Fig. 2, not shown). Centring.-In a preliminary step to find the centre of the hole pattern, the target is scanned line by line for two perpendicular directions to ascertain which two perpendicular lines have equal numbers of holes on each side, their intersection being the centre.
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