My first 77/22 didn't have the loose bolt issue. However, it had a barrel from hell. Chamber was cut eccentric and oversized. Never got it to group. Eventually traded it off. (A Number-3 was likewise a stinker. Someone had cut chamber to .22KHornet and botched it).
My KBZ (Heavy barrel stainless w/laminate stock) has loose bolt issues. I've mitigated it by making a C-shaped shim to fix it . Took nearly a thousand rounds to "shoot-in" the barrel and find an accurate load. But, now it's a "keeper".