Anyone here know if I can fireform some 6.5 mm TCU cartridges in my 7 mm TCU bbl?
I sold the 6.5 some time ago and retained the 7 tcu,
but I have about 150 loaded rounds of 6.5 that I don't want to pull down (don't even own the proper puller collet for 6.5 mm).
Would this do any damage to my bbl?
I am thinking it would be o.k., but don't want to damage my 7 MM BBL.

I haven't done this but according to the chamber/cartridge dimentions the fireforming should work safely and fine as the shoulder and case measurements are almost exactly the same....I can't see where any damage could be done to the barrel.....you might want to run a dry patch down the barrel between shots to get the unburned powder out as the case won't have the bullet resistance entering the rifling to help build pressure for a good burn of the powder......hth..good luck and good shooting-fireforming!!!!

You can, you may loose a few cases to neck splits though. I have even fired .223 in mine just to see if it could be done.