What is the max effective range with a mosin nagant 7.62x54r?

If you really want to, you can shoot somewhat effectively at 1 mile. But the round loses energy around 500m (500m*3.28ft=1640ft) So about 1640ft, but this is dependent on which rifle you own. For example, since the m44 carbine has a shorter barrel, it has less range than the m91/30.

Hope this works for you