Camp I can't honestly tell you if those tubes are HS safe or not, I haven't sold them. I DO know that your buddy was full of crap as HS is much harder than copperplated lead tho! Alot of the problem with tubes is in the way they are made. Most of the $75-$100+ tubes are so expensive because they are machined from one piece of quality steel (stainless preferably). Alot of the cheaper tubes are actually built like old shotgun barrels, they are heated metal that is "rolled" around a mandrel to get their shape. They then have a "seam" that is welded shut and the result is a tube. Steel, HS and other non-lead shot can actually cause those tubes to seperate along that seam. That is why I think it is only prudent and safer to spend an extra $50 on a tube that you KNOW is gonna take the abuse.

If you blowup a barrel with HS and a cheap tube it's gonna cost you ALOT more than $50 to replace it. I look at a quality tube as not only proper equipment but cheap insurance for my safety and my guns protection!
RA