I went to the one web site and the rule of thumb dealing with wall thickness to bore size refers to CAST cannons. Black powder is low pressure. My dad made his golf ball cannon out of 4" steel and it has a 1 3/4" bore, that's only about a one inch wall. Do any of you have specific reference of specs using modern solid steel not cast using a liner. Here's a copy of what the website said, where does it say it applies to solid steel(not cast/lined) barrels.
All reproduction barrels manufactured after March 1, 1986 must have pictures of the liner and breech plug before and after welding. No reproduction barrel shall be approved after March 1, 1986, that does not have one caliber’s thickness of metal surrounding the bore at the breech unless approved by Artillery Ordnance Officer. (See figure 10.2 for example.) Liner may be affixed by casting barrel around the liner or by other approved methods such as bonding with high strength adhesives. The method of locking the liner in the barrel shall be approved by the Artillery Ordnance Officer. The gun and its crew must pass the inspection specified in Section 18. A gun crew shall consist of a minimum of four members of the organization. Effective 1 February 1996, all artillery pieces must be originals or full-size, exact replicas to be approved.
Let's consider a 3" 50 cannon, most of the chamber for it is in the barrel and it ( the barrel part of the chamber in front of the breech ) is not 9" in diameter and I guarantee that it operates at several times the pressure of the black powder cannons.
steel has a tensile strength that is around 50% higher then cast iron
INDYGUNWORKS
You say that DanB's, 7" piece of steel tubbing with a plug pressed and welded into it, sounds "fascinating and well buit". That's only 2" sidewalls with a 3" bore?
yet a solid piece of steel bored out doesn't sound safe?
please explain?
I wasn't trying to be a prick or hard headed. I was simply asking for something to back up your post or gives more info that shows where using solid steel follows the same "rules of thumb" as cast with a liner. If I didn't want the feedback or input I would not of made the post. It was not my intent to question your comment but more to question where the info comes from.
Please keep keep the info and feedback coming