Remington 7-1/2 primers have been around since the mid-1960s. One of the primary reasons for their introduction was a heavier cup, in order to contain the pressures of newer cartridges that used small rifle primers.
But have also heard and seen them called 7-1/2 Magnum primers, though I can only recall them being called Bench Rest primers. Does anybody have any older boxes of 7-1/2's that say "Magnum" instead of "Bench Rest" on them? Or know of any references to that effect? I can't find anything firm on the subject in my reference library, or on the Internet--except somebody recalling when the boxes said "Magnum."
Speer Number Ten reloading manual has a table st the button of Page 32 that lists Rem 7 1/2 on the Small Rifle Magnum line along with the Federal and CCI small rifle magnum primers. That's not necessarily definitive, but it's one reference.
