Originally Posted By: Drew Hause
This is what Bro. Compton said, which I totally do not understand

p. 129 The other variable which can be altered in the test barrel to change the internal ballistics is the chamber length. In Table 3.10 the standard deviation and pellet counts at 40 yards are given for a 36g load of #4 lead shot loaded into a 2 3/4” cartridge cases which were fired through a selection of chambers lengths. The averaged results show a definite alteration to the lateral dispersion of the shot cloud when using the wrong chamber length. The tighter pattern generated by 2 1/2” chamber length may be caused by the restrictive crimp opening acting like an internal choke.

OK Bro. Don; you're on wink


Doc, we're deviating a bit from the initial topic. However, recalling material I've read on using shells which, when fired, are longer than the chamber length of the gun in question, I took away the theory that those old paper cases--opening into the forcing cone--provided some cushioning for the shot charge that was not provided by the wad back in those pre-plastic wad days. Thus protecting more pellets from deformation.