If the OP could find those two old gents, he should challenge them to try that stunt. The shoulder of the 6.5 Creedmore is larger the shoulder of the 260 Remington, so it would involve swaging the case down to be able to close the action. Don't get me wrong, I'm not saying it cant be done! I've seen 308s fired in 30-06 chambers, 270s fired in 30-06s, 8X57 fired in 30-06, 300 Savage fired in 308, 243 fired in 6mm, stuff like that. But it would be challenging to say the least.