I spoke to Dean yesterday afternoon. He is in the middle of moving to his new shop, but still gave me about 20 minutes of his time. Super nice guy.
He didn't have his notes with him, but said he thinks the current thickness is about .027. He said smaller bores don't need 30 thousands. After honing he said the MWT would be less than .020. He also said he would shoot the gun "as is". I'm probably going to send the barrels to Briley for 28ga tubes. Hopefully they can give me better info as to exact measurements.
