Spell strike Ammunition

So question for the room. Looking at the activation requiring the Cast a Spell action and in the language it says “you activate spellstrike ammunition by casting a spell into the ammunition.”

That being said, is it possible for an archer to have someone else cast a spell into an arrow so it can be stored for later? Seems like by RAW the answer is no, but I really want to be able have a wizard cast a scroll of shocking grasp on a spellstrike arrow that I can store for later use.

Under consumables in core rulebook. Activated ammunition: you use an action to "launch" it and additional actions to activate it. It all happens when you fire it. So no casting and storing.

From the consumable rules:

"Once you activate the ammunition, you must shoot it before the end of your turn. Otherwise, it deactivates (but it isn’t consumed) and you must activate it again before you can use it."

So no.