Loading 223 with the components that I already have

[2ndtimer]

MY barrel is 5.56 NATO but the brass is .223. I am starting with the minimum in the Hornady book

Basically no difference between .223 and 5.56 brass. If you have concerns and are loading warm to max loads, be aware that some brands are heavier than others and have less internal volume. In my experience, LC NATO brass differs very little from most commercial .223 brass, while some commercial .223 brass is heavier than military surplus brass (CBC, PPU and maybe Starline). Doesn’t mean that those are bad, just that they might increase pressure due to less internal volume.

 

[AJC1]

MY barrel is 5.56 NATO but the brass is .223. I am starting with the minimum in the Hornady book

Load a 3 round ladder from min to max in half grain steps to check for function, pressure signs, get crono numbers, and if you have access to a range 300 yards, run the ladder poi test at the same time. A lot of tests can be run in parallel if your wise.

 

[HEAVY METAL 1]

Your initial reasoning has nearly come full circle with regards to price of components in my area at least. My loads are ~ $1-2.50 a box less than purchased new ammo.