Guys,
The TexasTactical matches are basically like IDPA matches, but with rifles. Ranges are usually a little greater, but the berms/bays that they are set up in limit it to 25 yards. Sometimes stages are done on the 50 yard line of the rifle range.
Usually you won't have to fire more than 20 rounds in a stage. Some will force you to download your first mag to force a reload. Usually don't need more than one spare mag, but two are beneficial.
Thus, you would need something to carry a couple spare magazines.
You must also carry a pistol for backup. Pretty much anything you can use for IDPA will be acceptable. A couple extra mags are good, and some way to carry them.
As far as what weapon you use, you can use pretty much any rifle you would pick up in a SHTF situation. Most people use ARs. Myself, I've used an M1 Carbine and a semi-auto Thompson, but built a 16" AR due to the sheer practicality and ergonomics. Optics are allowed. Full auto used to be, but due to the range owner's rules, no more. Having a sling on the rifle is beneficial. Some use tactical slings on ARs, which is the setup I have going now... it's sweet... anyway...
For the whole match, you'd want to bring at least 100 rounds for your rifle and probably 50 for pistol (even though you might only shoot one magazine from your pistol). Bring some water/refreshments (the guys that run it bring water, too) and some sun screen and maybe a chair.