The 7.62x39 cartridge has an effective range of 500m. But I read online that with a match grade 110 grain bullet, and the casing full, you can push it further. The 7.62x54r is actually not a very good round, the recoil is about 2 x as much as the 7.62x39. That's why they developed the 308 round which can push even further than the 7.62x54r. When shooting a 308 in comparison to a 7.62x51, you feel the recoil increase. Take a 308, load it with 7.62x51 and a SKS to the range, you can see that you are usually done after 20 rounds of 7.62x51 but keep on shooting the SKS until you run out of ammo. There is not much demand for 7.62x54r even with so many Mosins around. 7.62x39 all day long.