Step 1: Getting a gun/ barrel
I recommend a good sturdy gun, like a tippmann model 98, A-5. or
Other guns, like Spyders or pumps, can work very well
If you already have a good working gun, i would recomend a good, acurate after-market barrel. If you have the extra green, get a barrel with multiple insert bores. If you have a tippmann, get a flatline, cause nothing will work as well with that type of gun.