they said it would cut costs in half
That was just my thumbnail sketch. It depends so much on what you blow out the tube.
Take a 69gr SMK 223. Yeah, not the best way out there, but will do really good for the first 4-500m. They can be had for about $160/500. 308 175 SMK from the same shop is $265/500.
Both will use many of the same powders, but the 223 will use about 25 grains, whereas the 175 will use say 44 grains. Brass, primers, time are all about the same.
Plus, with the 223, you are not likely to be sore, or flinch.
Take this with a grain of salt though. I hunt my LR rifles. They are 30 cal. I shoot as much 223 out of ARs out to 500m as I can though(300 rnds today