If you're into the Tippmann Paintball Guns, you've probably heard of the Flatline Barrel. It's known for imparting a spin on a paintball to increases range of over 100ft over other paintball barrels. This makes it the barrel of choice for Paintball Snipers and Milsim paintball players everywhere. The A-5, X-7 and 98 Custom/Pro Flatline barrels all work the same. We'll use the A5 version to help you understand How the Flatline Barrel Works, How to Adjust the Flatline Barrel and ways to Upgrade or Modify your A5 Flatline. So if you are experiencing problems with the flatline barrel, this article is for you.
The A5 Flatline is basically made up of 4 parts. It has an endcap with a barrel adapter molded into it. A 9.25" curved barrel, yes curved! A solid barrel shroud and a front end cap.
There are three screws that hold the barrel together. There are two outside screws that hold the shroud to the endcaps and an inner set screw that locks the barrel to the rear endcap.
Take a look at the barrel, it has a slight curve to it. Also the inside of the barrel is not polished or rifled, in fact it's quite rough. The combination of the slight upward curve and the rough surface inside is responsible for creating a spin on a paintball as it's shoot down the barrel. This spin is believed to cause a directional momentum allowing the paintball to fly further and be more resistant to outside factors than a paintball shot out of a standard barrel. Does the flatline barrel really work? Typically the Flatline averages about 100 ft further than the normal barrel. You also get further straight trajectory.
The A5 Flatline does not require the use of the A5 Barrel Adapter included with your stock Tippmann A5. If you loosen some of the receiver scews and the screw holding the cyclone feed system on, the receive halves will separate slightly making it much easier to remove the barrel adapter. We actually keep the stock barrel threaded to the barrel adapter when removing the adapter. It's just easier because the barrel allows for more grip when turning.
The single most important thing about the flatline is that it must we lined up correctly to the rear endplate to work successfully. In our experience with these barrels, Tippmann does a great job of shipping them out perfectly 'adjusted', meaning the barrel is properly aligned with the back endcap. It's unlikely you'll need to adjust your barrel. If your barrel is acting odd when using quality paintballs, chances are the barrel is not properly adjusted or has moved out of alignment. With the shroud and front cap removed take a look at the barrel and the rear endcap. On the barrel you will see a etched line from the factory (see picture below).
That line marks the center of the barrel and the mark to which to line up the set screw inside the back endcap. If the set screw notch is not in the middle of the barrel's line, simply loosen the screw, line up the barrel's center mark with the middle of the set screw hole and retighten the screw (see picture below). That's it, your A5 Flatline barrel is adjusted.
The A5 Flatline barrel is unique in that it allows for easy modification by simply replacing the barrel shroud. With the removal of the two exterior screws, you can achieve various looks and functional capabilites by replacing the A5 Flatline Shroud. Paintball companies like JCS, Trinity, Metadyne and Proteam make aftermarket A5 Flatline replacement shrouds. Some offer just a cosmetic change by milling holes or patterns into the shroud. Other shrouds are equipped with tactical rails for adding accessories such as a laser sight, tactical flashlight or front grip. You will commonly see these shrouds referred to as an RIS system. RIS stands for Rail Interface System. Majority of the rails associated with these flatline shrouds are standard military width (7/8") so even accessories that are not specific to paintball are likely to work just fine.