I haven't tried the Copperhead yet, but always liked the idea. My thinking now tends more toward the .257 TCU. Even have a barrel blank waiting for one or the other.
I too had a sillywet shooting friend that swore by a (relatively) pipsqueak 7mm cartridge - the 7TCU. He had it set up for "no size" reloading. The necks were tight enough so that after firing and neck springback, there was the correct tension on the bullet to hold it for the next shot.
Regards,
Scott
