Gamebore 12ga 2.5 Pure Gold too hot for a classic double Ithaca flues at 1295 fps?
Probably ............. because few loads at 1295 are going to be low pressure loads, but if you could provide the chamber pressure we could answer definitively.
SRH
How can that be provided?
Only by requesting the information from Gamebore. Some companies will provide that information, some will not.
Edited to add .............. There is another way. You could send some loads to have them pressure tested. That would be even more definitive, IMO.
SRH