A friend said he was making 6.5cm from .308. I was wondering if anyone here is doing the same . I thought the 6.5cm case was based on .30TC, and have zero experience with the .30TC.

The .30 T/C is basically the .300 Savage, and yes, apparently Hornady claims that's what they based it on. The .308 is slightly longer, and would work as well. But the 6.5 Creedmoor also almost identical to an older wildcat, the 6.5/.250 Savage RCBS Improved.

It would be relatively simple to make 6.5 Creedmoor brass from .308s, but dunno why anybody would bother, since even during this "shortage," 6.5 CM brass appears all the time on the Campfire Classifieds--and is far more easily formed from .22-250 brass, which is still relatively abundant. Unless, of course, your friend already has a bunch of .308 brass.

Accidentally shoot a 250 Savage in your 6.5 sometime

I was most interested the amount of work involved. I didn't know if the case had the same rim and base cross section. Thanks for the input. I mentioned just buying brass, but my friend has buckets of .308, and is tighter than bark on a tree. He also needs something to occupy idle time. One of my concerns, I don't like cases with the incorrect head stamp!