When Ohio Rapid Fire was a going concern and 5.45x39 surplus was just starting to come around in bulk, the (10) Bulgarian WASP ammo was available before the Ukranian/Russian stuff that is typically available today. I shot one sealed can of the Bulgarian ammo before switching the the Russian ammo. I didn't notice any difference in power or accuracy, but I do believe the Bulgarian ammo shot cleaner than the Russian, based simply on cleaning my rifle afterwards. It was also newer production, if I recall correctly.