Broken Shell Extractor

Single piece cleaning rod, new 30ca brass brush, send the rod down the barrel from the muzzle and out the chamber through the case, screw the 30 cal cleaning brush on the rod, pull the brush into the case until you get the rod end of the mop to the neck section of the split case, the rasp the cleaning handle off the floor to drive the cleaning rod with mop back out the chamber.

Hence as you pull the brush into the split case, it's bristles will bend backwards to angle to the inside of the walls, and as you drive the rod back with brush in tow, the angle bristles get a good bite on the inside of the case to grasp and drive  it back out with the handle blow.

Once you have the spent case removed from the chamber, unscrew the 3o cal cleaning brush and spent case from the cleaning rod, and throw them away (the brush will be destroyed by the time to try to get it out of the case after it bites into it.

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As for barrel, figure it toasted.  Hence to blow up a B/C that badly, the bore was obstructed when the round in the chamber was fired, so where the obstruction was (second bullet in the barrel, in front of the ignited rounds bullet) the bore will be budged/barrel walls weakened.

https://www.ar15.com/forums/ar-15/Can_anything_in_an_UPPER_cause_a_kaboom_/66-696184/?

So on a KB upper, rear sight items, FA items, FS/brake,  barrel nut/delta, as well as gas block can be reused, but the main upper and barrel, they are trashed instead.  Hell, if the KB is bad enough, it will balloon the lower receiver at the mag well area, so although the lower receiver parts can be saved, the lower receiver itself it trash instead.

So from a Smiths stand point, clean the barrel once you get the spent case out, then run a tight patch on a jig with resistance down the bore to find the bore budge, and mark it on the barrel.  Now when you have the customer back in the shop, send the patch on jig back through the bore again, so the customer can feel the budged/no patch resistance at that area budge spot via the cleaning rod as well.

From here, you can cover the base with them that you suspect they had round that failed to fire, went to cycle the round out, but only the case was cycled out to leave the bullet from that round still in the barrel, new round was cycled in, ending up with a bullet in the barrel in front of the bullet in the second round, and what KB'd the rig.  After this, then you can go through the list of what small items can be saved to be reused, while what items will need to be replaced since they are no longer safe to reuse, including the barrel, and if they want you to repair the rifle.

Note, don't be surprised to find the budge much father first down the barrel than just after the barrel leads, since I have seen rigs KB but someone leaving a clean brush or path with Jig in the barrel farther down that unscrewed from the cleaning rod they did not catch when cleaning a barrel, as well as someone using the muzzle of the rifle as walking stick/tripping to jam the muzzle into the mud, to pack the muzzle end of the barrel with dirt/mud as the obstruction instead.

Bottom line, you touch the rig to repair it in any fashion, it's your liability insurance on the line, so any parts on the rig that are questionable in any way are no longer deemed to be safe to be reused.  If some of the parts are bad enough, then they are not sent back out of the shop with the customer for any chance of being reused once you have repaired the rig.

So again, find the cause of the KB, get the customer back in the shop to show them why the rifle KB in the first place, and then you can go over if they want you to correct the rifle to get it running again/ what it going to cost, or if you are just going to send them off with a box of dissembled destroyed parts isntead.