Yeah sounds possible depending on build. The following was an exercise to see how crazy I could make a wizard archer, typically I'll do a build to see the potential so i can dial it back to an appropriate level for actual play. This rough build uses a +1 adaptive Huge Great Crossbow with enlarge weapon cast to make it gargantuan. In actual play I would probably just be using a standard light crossbow or sling with way less min/max going on.
If all the shots hit, it averages something like 110 damage. Potential crit of 330 dmg or something, but thats nearly impossible. Reload wonkyness comes from Collar of perpetual attendance, along with Adaptive weapon shenanigans. Feat tricks at first level are from options to swap out familiar for a feat, and options to get fighter feats instead of wizard bonus feats.
Super xbow build
Lvl 6 Focused Conjuration Wizard 32 point buy Race: Glimmerfolk
Str: 10
Dex: 20
Con: 14
Int: 16
Wis: 8
Cha: 6
Weapon starting stats: Huge Darkwood Great crossbow (4d8 18-20 critx2) +1 Adaptive (56 pounds lol?)
Active effects: Alter self to dwarven ancestor(large), enlarge weapon spell (6d8),
Flame Arrow, Haste 3 attacks, bulls strength/muleback cords(pf)/lifting belt(pf)/ant haul spell(pf)
hit/damage
knowledge devotion +4/+4 (insight bonus)
Bab +3/+0
Dex +5/+0
Rapid shot -2/+0
Point blank shot +0/+1
Haste +1/+0
Size -1/-0
Greater MW spell +2 +2/+2
Hand crossbow focus +1/+0 (combination with adaptive allows free reloads)
Weapon (huge) penalty -2/-0
+11/+7
Full attack, 3 attacks, if all hit 18d8 + 21 + 3d6
Damage: (calculations done assuming both bolts at least roll a hit)
Averagenon crit:
Max crit :
Significant Defenses: Scintilating scales, haste, alter self (dwarven ancestor)
Haste +1 AC
Size -1
Mage armor +4
Dex +5
Natural +18
AC: 37, Touch: 23 incorporeal: 27
Feats:
1st: Point blank shot, Knowledge devotion, Collegiate wizard, Metamagic: extend spell, 2 flaws
3rd: Exotic weapon great xbow
5th bonus: Hand xbow focus
6th: Easy metamagic: extend spell
Knowledge checks
Collector of stories +5 competence
Tools (50g per knowledge) +2 Circumstance
Ability bonus +3 ability
ranks +9 ranks
Absent minded +1 Untyped