I took the time to read it carefully this morning Semi. Very nice job and excellent story and documentation. I hope you don't mind if I ask one question. Is the steel you used to mill that breech block out of just regular mild steel or is it harder. Maybe mild steel is all that is needed there because the pressure seems like it should be confined to the barrel and that short flame channel.
I commend you for your hard work and patience. I'm looking forward to seeing how it shoots!