Since .57, including .58 it only spawns on the SVD. This really defeats the purpose of the scope being usable on AKs since no one that actually finds an SVD will cripple it to use its scope on an AK.
In addition, in the event the scope itself gets ruined, the SVD essentially becomes worthless as the only way to get a new scope is to find a completely new SVD.
I recommend that either PSO-1 scope should be a rare spawn in eastern military loot zones (let's say two to four times as rare as the Kashtan), or it should have its own spawns on Heli crashes, a top of spawning on the SVD.