feeding problem with m77 mark II

ionlyhave1problem,
Welcome to the forums! Have you checked to make sure the inside of the magazine box is clean and the magazine follower is not getting hung up or dragging when it’s down to where it would be when there are 2 rounds in the mag? To offset a possible weak mag spring have you tried holding the rifle on its side or upside down and seeing if round 2 feeds then?

Yes, I've cleaned the entire rifle and checked everything to do with the magazine box and the follower and it doesn't get hung up on anything.

As for holding the rifle upside down chambering the first round is fine. When I pull the bolt back the second round nearly falls out of the rifle.

When I put it on its side and try to cycle it the same problem occurs when it's upright.
I really don't have a clue.

OK, how does it behave if you only load 2 rounds instead of 3? Round 1 OK and Round 2 not so much? Or, does Round 2 work fine then? Trying to see if the follower height seems to play a part.

If I only load 2 rounds it works perfectly fine same if I only load 1

Progress! Easy solution - never load 3 rounds! Just kidding. I've got to think that either the follower is getting hung up on something or the spring is bent, not seated, or pushing the follower up at some kind of angle that's causing it to twist or bind up. Floor plate not seated 100% maybe and sending the spring up at something less than the ideal direction? Is it possible the spring was put in backwards or upside down at some point?

haha
The spring could be the problem as I think it has been bent out of wack by the previous owner.
I've double checked the spring and it is in correctly, the floor plate also seems okay.

If the spring has been pushing off center, maybe the inside of the magazine has finally developed a little burr or gouge that the follower is getting hung up on. Feel around inside with a Q-tip and see if it gets hung up on anything.

I checked all over the magazine box with a Q-tip like you said and didn't find much

Did you check the follower for any burrs? If you find any you can polish them out, I do this on mine regardless.

Try taking a pencil, erase end down....start at the center of the follower and compress the spring and slowly release it. Do it multiple times, if it doesn’t hang up move it back some and repeat. Do this until you’ve come all the way to the back of the follower.

If you’ve polished the follower and it still hangs up you need to look at the spring. More than likely you’ll need to bend the spring a little. Remove the spring and at the bend closest to the follower, (using two needle nose pliers) open the bend up slightly, this will increase upward pressure on the follower. This has worked for me.

Worst case call Ruger and get a new spring.

I've check all over the follower and it's fine I also polished it just in case.
It doesn't seem to me that the follower is getting caught on anything but rather having a hard time lifting the rear end of the round.
I will try the pencil trick when I get back home.
Thank you.