Oneshot,
I will preface this note with a fact about me - I believe that if you are going to kill do it quickly and cleanly.
The 7,62 x 39 is less powerful in a Contender than a 30-30. Less powder space with same weight bullets. The difference isn't a lot and I will agree that with a properly placed shot it is capable of killing a deer at 200 yards. I will add that, unless the shot presented is right and the placement of the bullet is correct you will only wound the animal with little chance of recovery at that distance.
My advice is to hunt close and shoot well.
PaulS