The transverse magnetoresistivity of pure tungsten and molybdenum single crystals was measured in temperature range from 2 to 80K and in magnetic fields up to 30T. The samples contain chaotically distributed dislocations produced under deformation by compression and dislocation walls formed during crystal growth. It was shown that dislocations strongly affect the magnetoresistivity of these pure metals. It was demonstrated experimentally that the peculiarities of the electron-dislocation scattering and its contribution to magnetoresistivity substantially depend on the dislocation structure. The electron interaction with the chaotically distributed dislocations leads to a change of the electron orbit types and to the dislocation breakdown. The electron scattering by dislocation walls can lead to the internal static skin effect, i.e. a concentration of a dc current near walls of dislocations. We discuss some possibilities to use the magnetoresistance effect as a new method to analyze the dislocation distribution in pure metal single crystals.