In the 1950's outfits like Ye Old Hunter/Hunter's Lodge, and others imported them when they were gathering surplus military arms from around the world. Whether they came direct from Russia or a satellite country I do not know. Most were the worst for wear, with a good one occasionally found. Something close to 300,000 were shipped to Russia in the 1915/1916 time period.
The warning about headspace should be heeded. The receivers were prone to stretching with some of the newer smokeless powder loads.