I can't fathom not doing the longer 6.5x55 on a LA pre-64. It begs for the round, especially given the fine Lapua brass. I'd absolutely do a Roberts on the pre-64. Due to SAAMI's (Remington's) silly throating, bullets can be seated out to make a 3"+ cartridge... modern SA's on the pre-64 action are just "wrong"... it's a fine, classic action that needs a fine, classic cartridge.

I'd sooner use a USRAC SA for a 260, which is SAAMI throated to work in a 2.840" mag box. laugh


“Perfection is Achieved Not When There Is Nothing More to Add, But When There Is Nothing Left to Take Away” Antoine de Saint-Exupery