Seems to me the gun had the forcing cones lengthened and most likely had the bores honed out and were too thin.
The gun looks redone, so who knows what had been done to it.
Only Barnett would know.

I seriously doubt that someone borrowed it and shot heavy loads out of it. Someone that might have been thinking about this gun and willing to pay the price would know not to shoot 10000 psi loads or higher.

David