I have never shot a 28ga damascus but can tell you, the 20ga load for my damascus Flues was at 7200 psi.
The barrel walls were checked before hand and I was comfortable with the findings.

Rev Drew's posts and Burrard's books have always been my first stops before making decisions concerning pressure.

Hope this helps!!

Last edited by ithaca1; 05/08/23 08:50 AM.
Bill Johnson