Holy Frijole! Let me measure mine....
.020 on flat spot (dirty) and .027 across compressed fire ring. So those bade boys are .040 uncompressed! With the 70 ft/lbs (dry) torque on those bolts they have a clamping force of 9,550 lbs. If you lube the bolts and torque them to 70, that increases the clamping load to ~11,700 lbs....!
I wonder if you could take a .012 stainless wire under those fire rings and beat a new .040 onto them with a rubber mallet? Or just run it again with some copper spray.