Sooo.... exactly how broken is this ability?

So I'm helping my friend make a supernatural-inspired Castiel, but with a twist: GUNS.

I had the crazy thought to grant him an ULTIMATE ability to unload all his custom-made guns ALL at once in one turn:

• Can be used once per level up (14 max usages)
• All Guns attacks receive a guaranteed Hit
• All Guns attacks receive a guaranteed Crit
• Empties all bullets currently in all his weapons
• Afterwards, he has to roll to see which guns jammed because he stressed each one out
• All weapons are empty after attacking

Damage Calculation for his ULTIMATE ability:

Proficiency Bonus

|| || ||3|||| |Spiritus Sancti|Damage|Crit|  Max Damage|Max Crit| | Long-range repeating lever-action rifle|95|190|95|190| | 2 Six-Shooter Revolver |324|648|324|648| |Sawed-off double-barrel shotgun|30|60|86|172| | Six-shooter Revolver long barrel Shotgun |114|228|318|636| |Total|563|1126|823|1646|

His weapons:

|| || |Name|Damage|Attacks|Weight|Properties|Notes|DC| |Holy Knife Dagger|1d8 Piercing|1|1 lbs|Finesse, Light, Thrown (Range 20/60), Nick||| | Long-range repeating lever-action rifle|2d8/2d10 Piercing|5/1|8 lbs|, (Range [120/360]/[150/600]), Reload(5 shots/1 shot), Two-Handed, Misfire, SapAmmunition (Firearms) |His signature Long-range repeating lever-action rifle (Range 120/360) that shoots five shots (.300 Winchester Magnum rounds), but can be converted into a single-shot even longer-range sniper rifle (Range 150/600) by twisting off the ammo barrel underneath to extend the barrel. (he sacrifices 5 bullets for 1 bullet that shoots father and does extra damage.) But it takes one turn to set up the rifle in either configuration, but he can hot swap either one after he brings it out and sets it up.|| | 2 Six-Shooter Revolver |(2/4)d6 Piercing|12|4 lbs each|, (Range [30/90]), Reload(6 shots/each), Light/Handy, Misfire, VexAmmunition (Firearms) |(.500 Bushwhacker, with a pentagram circle on the wooden handle)|| |Sawed-off double-barrel shotgun|3d4 Piercing|2||, (Range [30/90]), Reload(2 shots/each), Light/Handy, Misfire, Push(<=60ft), Special(if fired with 5ft/10ft, it instead does 4d10/4d4), Spray(Close targets have higher DCs: 5ft= +10DC, <15ft=+6DC, <30ft=+4DC, <45ft=+3DC, <60ft=+2DC, <75ft=+1DC)Ammunition (Firearms) |(So he can duel wield with either his Holy knife dagger or Six-shooter Revolver. Also shoots like a cone.)|Dex Save DC=8+Dex+PB| | Six-shooter Revolver long barrel Shotgun |4d4 Piercing|6||, (Range [60/100]), Reload(6 shots/each), Two-Handed, Heavy, Misfire, Topple(<=60ft), Special(if fired with 5ft/10ft, it instead does 5d10/5d4), Spray(Close targets have higher DCs: 5ft= +10DC, <15ft=+6DC, <30ft=+5DC, <40ft=+4DC, <60ft=+3DC, <80ft=+2DC)Ammunition (Firearms) |(Shoots like a cone)|Dex Save DC=8+Dex+PB|

He can switch to Holy bullets with bibble verses written on the cartridge.
He can switch to healing bullets, but he has to get past his allie's AC to land a heal on them.