  A mechanism for creating well-collimated beams of neutral particles or atoms
with spins is studied. The consideration is accomplished for a general
realistic case, taking into account: (i) the finiteness of a cylindrical trap
where the atoms to be shot out, are stored; (ii) the possibility of
manipulating the trap magnetic fields in order to form different anisotropic
field configurations; (iii) the presence of gravity curving atomic
trajectories.
