Skeeterbd,
S&B is an old line company and knows very well the difference between the rimmed JR and the rimless J cartridges.While I don't have the cartridges "in hand" to check,I see signs that they have had original rims removed.I speculate that a non-handloader had a bolt action rifle chambered for 8x57J and arranged for the rim of 8x57R cartridges to be removed, without changing the marks on the box and headstamp.There seems to be a great gnashing of teeth when it turns out that a rifle was intended for J ammo(.318)and this seems to be a novel way to make ammo;it seems to have somehow made it to your friend that had no way to know it had been modified. Your intention to continue using JR ammo is fine, but be advised that unmodified S&B ammo will also work.
Mike
