Troubleshoot my rifle misfiring?

[Q_Sertorius]

Probably a differently thread, but I’ve never shot a rife that seemed more influenced by the barrel heating up. Both times I’ve taken it to the range (when it shot), it seemed like the first 2-3 shots were right in top of each other, and after that it opened up to like 2” MOA. I know that’s not much data, and I probably flinch more the more I shoot (but that doesn’t happen w/ my 30-06). Any similar experiences with M77s?

Old Ruger barrels (approximately pre-2000), were generally garbage. I know that will offend a few folks and some will probably bring out their anecdotes, but they were not properly made.