I see now what disappears without Modern options - Bullets for my .44 Colt Army pistol. There is a generic 'Ammo' option which would seem to be similar, but the price is $1 for 50, while the Players Guide list them at $3. I guess I can take a discount.
But those are not able to be tracked as single bullets/ammo in the "In Play" section...so not really as helpful.