I have a cast action Ballard rifle and sometime in the past someone lined it to 38-40 using a 5/8" liner. The rechambering quality was exceedingly poor and it is kinda a 4" group, 100 yard shooter.

Between the poor accuracy and me wanting to rechamber to a smaller case head (32-20WCF or 25-20WCF) for pressure concerns, I am stuck with this old 5/8" liner.

If it is removed, there are no 5/8" 32-20 replacements from TJ's or Redman. Those aren't options.

Just drilling out the existing 5/8th" liner to 1/2" and installing the 1/2" TJ's 32-20 liner works operationally, but is that a real safe option?