I have shot to around 600 yards (at 14" square plates) with Radway Green surplus with some success.
For a full-length (20") FAL, I am planning to use established 150 and 168gr loads. For a carbine (18"), and I am experimenting with the lighter loads. I will post the results I get.
The FAL I was using for testing may not be inherently accurate enough to use for load developmend - sigh.