Can a player cast spells or activate abilities after losing priority but before the next player receives it?

When a player passes priority, they immediately give up the right to act. Priority then moves to the next player in turn order (or, if all players pass in succession, the topmost spell or ability on the stack resolves). There is no window between one player losing priority and the next player receiving it — the transfer is instantaneous and governed by CR 117.3 and 117.4.

CR 117.3 states that a player may cast spells, activate abilities, and take special actions only when they have priority. CR 117.4 explains that the active player receives priority at the beginning of most steps and phases, and that after a spell or ability resolves, the active player receives priority again. Neither rule creates any gap or interim window for action.

Similarly, CR 117.1 confirms that only the player who currently holds priority may take game actions (outside of special actions like paying mana or activating mana abilities in specific contexts). Passing priority is a discrete, atomic event — you either have it or you don't.

Concrete example: You cast Lightning Bolt targeting your opponent. Your opponent responds by passing priority back to you. You then pass priority as well. Lightning Bolt resolves. You cannot slip in another spell "between" passing and Lightning Bolt resolving — there is no such moment. After resolution, you (the active player) simply receive priority again per CR 117.4.

The only nuance is mana abilities (CR 605.3a), which can be activated without using the priority system entirely, but those are a narrow exception and do not allow casting spells or activating non-mana abilities outside of priority.