I'm currently reloading 223 on my Star, (just beginning in fact). I was fortunate to purchase a Phelps tool head that was remachined to accept 7/8x14 threaded RCBS dies.
The size & seat stations on the tool head were the ones that were reworked to 7/8". The heavy cast "collar" portion of the tool head that rides up and down on the Star machine shaft was also cut away in a rounded shape to make room for the size die to tread into the larger diameter hole.
The powder slide housing had an angle shaved off of the edge that would otherwise contact the 7/8" seat die, (again larger hole and diameter issue).
I had to shorten the screw on the seating die, as it interfered with the screw that attaches the spring to the tool head.
A .380 shell plate will work for .223, but if you tap the tool head for 7/8" dies you'll need recesses cut in the shell plate to accomadate the larger diameter mouth of standard sized dies.
I purchased a 223 powder spout, and expander plug from Manuel on this forum. Your sizing die will expand the cases, but I just wanted an expander on top of the prime station to help stabilize the brass.
I've chose to size my brass on a single stage press using an RCBS "X" die, (the X die eliminates the need to trim brass once you've properly processed the cases, and it's very important on the Star to have all brass the same length to prevent crushing, and to maintain uniform head space).
I made the decision to size brass on the single stage press because it seemed to require a bit more pressure on the Star than I wanted to use based on the volume of reloading that I'm anticipating.
I believe that there is an individual on this forum that could create 11/16x24 dies for you in .223, and thus eliminate modifications to tool head, powder slide housing, and shell plate that you'd encounter if attempting to use standard dies. He is mentioned repeatedly on this forum, and is highly recommended.
I recommend also the items that I bought from Manuel on this forum. I bought the Phelps tool head from Bruce here on the forum, he's great as well.
I've reloaded about 150 rounds twice now...I'm waiting on military brass and a primer pocket swage tool. They are loaded to M855 specs but in .223 cases, (to eliminate dealng with primer pockets at this time). The ammo seems to be more accurate than the factory PMC I have. Quite reliable as well.
I'm hoping to get together some pics of what is going on with the .223 & Star setup that I'm using, but not positive as to when I'll get all of that together.
Hope this helps... reloading 223 on the Star can be done, and will speed up your production above that of a single stage press.
Warmest regards