Reddit mentions of Barrel Threading Stainless Steel Die Starter (3/4-24.223/5.56)

Yes, but unlikely the same thread pitch that is commonly used on AR's. His is probably tapered pipe thread stuff, where this will be standard straight cut threads. You're going to need to look for 5/8-24. If it says NPT, or I think anything with a "P" in the 3 letter designator, it's tapered and a no go (unless you want to build your own muzzle device and thread it to match!). Tools shouldn't be expensive if you're a good and steady hand at taping. If not, bore alignment tools will center you up.
Die
Die handle (you'll need to figure out which size is correct for the die diameter)
Use this guy's advice to get the threads cut as close to the shoulder as you can
Out of stock, but you get the idea