Hi,
I do not want to open a can of worms but for what I have seen that seamless tube with thick walls can stand normal black powder charges.
My friend Saverio Bonazza made almost 1000 .50 rifles and pistols with seamless lubes.
No one fail, a couple bugle when double-charged and many of those rifles are shooting to this day.
I’m not promoting the use of seamless tubes I’m talking about facts I witness.

Thanks
Martin