The beauty of the .223/5.56 round is the versatility, and the seemingly endless combination of loads due to an excellent selection of decent components.
A 9 twist @ 14.5" in length would suggest you are looking for something in the neighborhood of 0 to 300m, general all around shooting and nothing out of the ordinary for accuracy - does that sum it up?
For this type of round, I'd look to sourcing the following:
Brass - good, cheap once fired mixed brass from some of the folks on the board here. If you are not all that keen on that or range pick up, buy a few cases of the cheaper PMC 55 gr. (first choice) or the Federal XM223 55Gr. (2nd) and go though that first to create your brass stash (assuming you don't already have brass squared away). There is a common misconception that there is a large variation between .223 and 5.56mm brass - this is almost 100% false. You may have to swage or otherwise clear the primer pocket of the crimp, but this is true of civy and mil. Brass. As long as your loads are not balls to the walls, mix and match the brass with no worries.
Bullets - stick with a bulk purchased 55 or 62 gr. Projectile would work, and if you are looking for a bit better performance, the Hornady 68gr. HPBT and the Privy 69gr. Bullets are about the cheapest 'match' type bullets around. The 69 sierra match king is a good performer, but a bit more cash.
Primers - most will do fine. If you are looking for a bit more consistency, the various 'match' grade primers usually yield less standard deviation - but there is no guarantee of that. I've used them all with good success, so get what you can get, get it in bulk if you can to lessen the varriables from load session to load session.
Powder - I'm liking Ramshot TAC (ball) for the heavier stuff. (65gr. And up)
Higgenson's WC-735 is a good surplus ball powder for the lighter stuff.
Hodgdon's H335, H322 and Benchmark are good ball powders, and there are decent stick powders like Varget, H4895, and Benchmark.
For the most part all of these will start in the 24.0 gr. Location for a load.
Most if not all stick powders in this range will be case filled to the under side of the neck and be fine, but as always reference a manual or online data from the powder manufacturer and work up you loads with a chrony.
Oh, and for case trimming, I'd recommend a Giraud trimmer.
Crimp your loads with a Lee factory crimp die and get yourself a Dillon 650 to load it all on.
