[en] The dependence of few parameters (related to the laser gain) on the radial distance from the laser axis, is observed very easily in a large-bore Copper Vapor Laser (CVL). An 80-mm-bore CVL which has reproducible parameters for research purposes has been constructed. The temporal development of the gain at different radial distances in this laser has been measured. A narrow probing beam from a small CVL operating as a oscillator has been used for the measurements, while the large-bore CVL has been operated as an amplifier and probed by this beam at different radial points. The electric response of the laser has also been checked and lead to the conclusion that raising the electrons energy in the laser plasma entails higher gain. As the laser tube wall was moved towards the laser axis, a temporal lag in the gain development and a reduction in its size has been found. The temporal lag is related to skin effect which delays the penetration of the electric field in the plasma towards the laser axis. The reduction in gain is related to the radial dependence of the population of the laser lower levels. It has also been found that under saturation the average power per unit area extracted from the laser is weakly dependent on the radial distance. (author)