Just a thought,

The sleeved center section, which appears to unbolt the sections from one another, is there enough "meat" to put in a longer bolt and a spacer of some sort? On second thought, that probably wouldn't be strong enough.

Can the side pieces of the revolvers be swapped with the original shackles if they are perhaps longer?

Can a new C-section be fabbed to the lenghth you need on the part that unbolts?

Random thoughts...trying to kill time here at work.