Just loading some 7.5x55 tonight, using a bag of 100 Remington .30 calibre 165gr. PSP bulk bullets. Included in the bag were a 150gr. HP .30 cal., three 110gr. M1 carbine bullets, and a 140gr. 7mm. bullet! 
These "bulk packs" you mention, are they from Remington? The only bulk packs I've seen in the past several years have been packaged by the shops that sell them.
I used to like buying the bulk Speer TNT bullets or the Hornady and Remington offerings that came in 1000 round boxes. Never once had a mispack.
As for a case in a box from the factory, without powder, possible but, the first one I've heard of. You should buy a lottery ticket. Did the bullet make it out of the muzzle when the primer ignited?