Need Help: Random ‘slow’ rounds

[TaperPin]

I’d bet lunch it’s an ignition problem - either dirty firing pin, bolt cocking piece dragging on the trigger, week firing pin spring, or weird batch of primers. If you’ve ever blanked a primer (had a hole in the primer) a small brass disk can blow back through the firing pin hole and cause problems.

I had a partially frozen bolt that had to be recocked a couple of times before it fired and it was almost 2 MOA outside where it should have been.