Investigation results on energy characteristics of CuBr+HBr lasers of large active volume with an externally heated active zone of the gas-discharge tube are presented for cases of the laser operation with different excitation schemes. It is shown that external heating by traditional pumping schemes does not affect significantly the laser output parameters. At the same time, the laser of such construction is able to maintain the required temperature regime of active medium independently of the pumping mode; this allows lasing in gas-discharge tubes of large volume at a low pumping power, as well as realization of the train operation mode. Based on experiments with trains, it is shown that escape of Cu from a discharge in the inter-pulse period is connected with CuBr reduction. The CuBr reduction rate constant in discharge afterglow is found to be 5 × 103 s-1.