Suponski's last entry was not Parker Special Steel. It was Parker Steel which was used on P grade hammerless guns. In my opinion, all of these steels can be safely used with the mentioned wall thicknesses.

I'll go with what Parker Bros. said; Sears catalog No. 112 1902 "BORED FOR NITRO OR BLACK POWDER"

https://photos.smugmug.com/Gun-Stuff...20Parker-L.png

And we know that the pressures of c. 1900 Smokeless Powder loads were very similar to the shells available today.

In light of the >100 year old wood however, it would be reasonable to choose lower RECOIL loads.

Thanks all for comments.

The gun in question has been restocked with "new" wood to adjust drop and LOP. I will still use lower recoil/pressure loads.

Again, to all that commented, thanks so much. What a great board this is to share knowledge.

I ve shot a lot of heavy loads in wire twist Damascus stub twist plain steel and fluid steel with smokeless powder and some black powder they have all held up to my loads so I agree with parkers statement about being bored to shoot all powders...charlie

Thanks Charlie.....