If you were to use a traditional 223 powder (fastish rifle powder) going for close to max velocity for that bullet, you're looking at about 20 grains per round. Plus or minus a few. So that's about 350 rounds, or so.
With the slower powders for that caliber, like say Varget or IMR4895, you might get around 280-300. Faster powders maybe upwards of 400.
If you're going to load a bullet as expensive as that one, you should probably do a little research as to the optimal powder, first. I'm going to guess it's cheaper to buy "standard" factory ammo vs 70gr Barnes. If you wanna load to save money, you might wanna try some 55-62gr bullets from Hornady, Midway "dogtown bullets," or if you're lucky you can find pulls. Even then, you don't traditionally save a whole lot of money loading 223. I haven't shopped factory 223 in a long time, so YMMV.
If you wanna load for better performance, well then you're in for some experimentation.