Never had any hunting pards who ever had problems with their early 77R's, but did hear a lot of complaints about the 77 Mark II's after they came out.
I bought a 270 Win 77R new in the early/mid 70's. I didn't have time to work up loads for it for that first years hunting, so just bought Federal Premium 130 gr ammo for mule deer and their 150 gr ammo for elk. Filled all my tags easily with this ammo despite some longish cross canyon shots, so never did bother to work up loads for it for several years. The rifle was a shooter right out of the box even with the store bought ammo, and took a lot of game for me in the 70's and 80's. I added a target trigger to it a few years ago and was going to put it back into action shooting long range varmints, but never did get around to it.
My mid 80's 77/22 was the same right out of the box, has seen a heck of a lot of use since without missing a beat and has killed uncountable small game and varmints. It now has a GM switch barrel in 17HM2 as well, that will make it even better IMO. I have three 17HM2's, but this one will be my go to if I can get out this year.
Only Ruger rifles that I've owned that I didn't care much for was their 10/22's. I've had 5 of them, the only one in the first 4 that was trouble free was a 10/22 International from the late 60's. Last one is a custom I put together with the best of everything, why I don't know. It saw about 50 rounds before it got relegated to the safe, and it still resides there. It's a purdy rifle but I'm not a fan of semi auto rifles at all, so I guess when it comes to semi auto rimfires I just can't get past my JC Higgins/High Standard 31 that I've had since the late 50's.
FWIW-YMMV
L.