Don't tackle anything you wouldn't hunt with a 30-30, and you’ll be fine. I think the Wolf 154 grain soft-point is one of the best factory loads.
Several years ago I tested then-available 762x39 ammo against my favorite expendable ballistic medium; water-filled 100 oz. laundry-detergent jugs. The rifle was a SAR-1 with a 16 1/4" barrel. I didn't own a chronograph at the time.
Two of the detergent jugs placed back-to-back will stop most expanding pistol rounds, and many centerfire rifle rounds. I haven’t quite figured out why- but they are real hard on bullets. I back them up with an old Kansas City phone book, braced against a section of 2x8 lumber. Shooting for this test was done at 10 yards. The photo gives an idea of the results, but the only round that penetrated both jugs was the Barnaul ball. It burst the first jug and exited sideways, passing through #2 with enough retained velocity to split it at the seams, and still penetrate about 2 ½” into the phone book. It tore a pretty good hole in that, as well.
Both of the soft-point rounds exhibited similar characteristics; each burst the first jug and tossed it several feet in the air; the main core fragment and separated jacket of each was recovered inside the second jug. Speaking of bullet fragments, it was apparent that may were shed and lost as the first jug was exploded by the soft-point bullets’ impact. The 125 grain Barnaul did a bit more damage to the first jug, than the Norinco soft-point did. The jugs appear in the photo below for your review and in each case the jug that received the bullet’s initial impact, is lying to the right.
And finally, the bullets themselves. The Norinco soft-point core weighed but 44 grains, and its separated jacket weighed 42.5 grains. The Barnaul soft-point’s core fragment weighed 59.1 grains, and its jacket weighed 23.4 grains. The Silver Bear ball round retained 120.8 grains through the ordeal, flattening itself notably as it plowed through the jugs and catalog sideways.