Most Russian surplus ammo is going to be berdan primed which is non-reloadable. Prvi makes a brass cased round that you could reuse the brass from. I'm not sure, but you may be able to use standard .308 cal bullets. It would pretty interesting to see what a mosin would do with 175 grain Sierra Match Kings and Varget powder. As far as dumping the powder, you could try using a kinetic bullet puller. You're going to need one anyway if you plan on getting into reloading.