[Wyosmith]

Absolutely correct.
An elk is big, but it's not armored. Archers kill them with arrows. Arrows from a 110 pound compound cam-bow will develop less energy than a 22 LR fired from a pistol. However when that small amount of energy is pushing a lubricated razor blade the penetration is enough to get through the entire chest of an elk.

The 7.62X39 with the 154 grain soft point bullets will kill anything you hit correctly with them. I would not say they are as fast at killing game as a 30-06, but your elk will fall and if you can track and follow a blood trail at all, you’ll find it within 100 yards I’ll bet.

I knew a poacher from Kooskie Idaho who used to kill them with a 22 Mag with 40 gr FMJ bullets. He had to hit them just right, but he killed every one he shot in the 7 years I knew him.

If we choose to hunt with anything, be it a bow, a hand gun, a flintlock or a 300 magnum, we need to stay within the limitations that we have. Those limitations fall into 2 groups.
#1 is the safe and reasonable limitations of our weapon.
#2 is the realistic and honest limitations of ourselves.
Taken together, those limitations provide a foundation for all ethical hunters to work within. I would call it unethical for you to attempt a 300 yard shot with your 7.62X39, but no more so than MOST hunters trying a 450 to 500 yard shot with their 300 magnum.

300 yards is a bit unreasonable for a 7.62X39, but if they are honest with themselves, a 500 yard shot for MOST hunters is too far for them to shoot with any rifle. Sure, the 300 can kill well at 3X that distance, but buying a long range rifle no more makes you a “sniper’ than buying a piano will make you into a musician. If you don’t have the skill to make a shot like that EVERY time, it’s outside your range.

If we take five 16 inch disks and place them on a hill, and tell 10 hunters to hit them all 2 time each on demand from where we say to shoot, and we place them around 450 to 550 yards away from the disks, you'll see what I am saying is true. About 20% of them can do it on demand. 80% cannot.

If you doubt me, get 10 of your hunting buddies together and try it. No practice shots, no warm up, no re-zeroing and no bench rests. Never do this at a shooting range where the shooters will know the distance. Always do it in the field so no shooter knows the range and must estimate it without aid. Just get into position and shoot, and all misses are noted. We are testing the shooters here, not the equipment.
Try it and see if I am right.

I do know some men and 4 woman that can do it every time. But I bet I know over 300-400 hunters that can’t.
How do I know this?
Because it’s a test I have used to prove my point to shooting students at the outset of my classes for over 30 years now.
Doubt me?
Go set it up and try it. Get your buddies out there and try it too, so everyone can see and every one is a witness to everyone else’s shots.
My point is simple.
Don't listen to the nay-sayers that condemn your rifle. If you are ethical, you will do fine. If you are a man that can and will turn down shots that are outside your effective range (of both yourself and your rifle) you are a true sportsman and a good hunter.

If not, it doesn't matter what you have, you are unethical and a "slob hunter".

That goes equally for archers, handgunners, spear hunters, muzzleloaders and high powered rifle shooters.

Your tool is far far less important than your mind, your abilities and your ethics.