There seems to be some confusion.
The proposal is to add the Returning prefix to the Conjured bolt spell already in the game not to add action points in trees to the game to accomplish this.
Instead of conjuring a stack of 1000 +1 through +6 bolts an Artificers Conjure Bolts spell would conjure 100 Returning +1 through +6 Bolts like arcane archers do with arrows. This tech is already in the game. Arcane Archers summon stacks of 100 Returning Arrows of different types already theres no reason Artificers shouldn't be able to as well.
When Arties first came out bolts were Conjured in stacks of 100 per use of the spell. So it took forever to make bolts before going into a quest. It was annoying and a stupid hindrance. A Dev that played arty agreed and changed the spell to Summon 1000 instead of 100 to save time.
Players would now like to see this further simplified to summon returners instead. Mainly because in long quests and raids, especially Epic Elites its common to go through several stacks of 1000 bolts leading to incidents of running out of ammo during the quest. Its no more overpowered or unbalancing than Arcane Archers summoning returning ammo.
If you must find a way to ensure we keep the spell in our spell slot make it so the bolts disappear when entering and leaving quests. I would gladly cast it once per quest to keep the rare occurrence of running out of bolts mid fusillade from happening ever again.