Model 98 Accuracy to Expect

Paintballs will be no where near as accurate as anyone with real firearms experience is used to.  That said, there are things that can improve accuracy.  Most of these items are covered elsewhere in the forum and can be found by reading the stickied posts or using the search engine so I will provide only the most basic info here.

• Paint--good paint is a must for accuracy; paint that is out of round, dimpled or has moisture on the exterior of the shell (such as from a broken ball in the bag) will not fly true
• Paint should be stored at the same temperatures that are comfortable for people; allowing it to get too cold will cause the shells to become brittle while overheating will lead to deformation
• It should be protected from exterior moisture which can cause swelling sufficient to render the paint too large for the feedneck/barrel
• Stock barrels are generally as cheaply made as possible and have poor accuracy
• This is because the manufacturers know that the eventual user will probably pimp out the marker with an aftermarket barrel anyway
• There are a lot of aftermarket barrels on the market; most of the people on here will recommend a J&J Ceramic or Lapco Bigshot in the 12-14 inch length range
• There are other fancier (more expensive) barrels available some of which come with fancy inserts to size the paint to the barrel; however, the recommended barrels above are more than sufficient for the average casual player or beginner
• Flatline barrels add additional range but the price of that range is accuracy
• This is not necessarily the fault of the barrel; paintballs, being spherical, liquid-filled, gelatinous, low-velocity projectiles fired from smooth-bore barrels are just not the most accurate of projectiles
• Flatlines (at least the older ones) were difficult to install correctly without practice and this leads to problems as well
• The barrel must be installed so the arc of the barrel is in line with the longitudinal axis of the marker; failing to do so (or holding it tipped to either side when firing) will result in the spin being imparted incorrectly on the ball and will cause the shots to pull to the side at longer ranges
• The barrel is large bore to allow the ball to spin inside it and this makes it an air hog as it allows air to blow by the ball; improper installation that allows air to escape around the breech can magnify this problem and result in low velocities
• Flatline barrels, in my experience, tend to be very particular about the velocities they are fired at
• 98 series seem to prefer velocities in the mid 270s
• A5 series seem to work better in the mid 260s
• Additional modifications, such as an expansion chamber for CO2, the addition of a rear velocity adjuster (to be used in conjunction with the stock adjuster) or switching to HPA can significantly increase the accuracy of the flatline; however, it will never be "sniper rifle" accurate--it is a suppressive tool more than a "sniping" tool
  
• On the subject of velocity; excess velocities have a negative impact on accuracy as well
• Additionally, for safety, no marker should ever be fired in excess of 300 fps anyway
  

Either of the two barrels in my other post are a good choice.  I like both with the J&J ceramic being my favorite (but not by much).

Both are fairly inexpensive as far as aftermarket barrels go.  (I've seen the J&J advertised in the $30 range before shipping and the Lapco as low as $50 before shipping costs.)  The J&J is "ceramic impregnated" which results in an interior surface that paint won't stick to.  (In other words, if a ball breaks in the barrel you can usually keep shooting and the barrel will "self clean" sufficiently well that not too much accuracy will be lost if you have to wait a while to squeegee it out.)  The Lapco barrel is of a larger bore size than the J&J which means it tolerates various paint sizes better than the J&J does.  The Lapco is highly polished and although it is not advertised as being "self cleaning" my experience is that you can shoot through moderate breaks with it and retain some accuracy.  (It does not do this as well as the J&J.)  I consider the consistency (accuracy) of both barrels to be about equal although the J&J (because of tighter bore) will handle smaller paint better than the Lapco.

Bottom line: Either one is a good choice. 

Just a note on the flatline.  I have found that the right paint is everything.  Using the cheap economy paint I was getting bad zingers.  I switched to marbelizer and at the arena I play at I believe they use breach paint.  Both are quite accurate.  I play woodsball and urban combat ball.  In woodsball I see the extra distance like this, when an enemy is hiding under a tree a distance away a standard barrel often cannot hit him because it needs so much arc the ball hits the branches.  With the flatline the ball shoots flatter farther, allowing me to slide the ball under the branches.  So while total distance may be equal with a flatline vs another barrel, the flatline will do so with less arc.

With practice you can be quite accurate with a 98 and flatline.  Yesterday playing urban combat I snap shot at an enemy, just 2 quick shots.  The enemy ducked back in time but I saw 2 paint splats on the wall right where his head was.

sorry been busy a few days.  The flatline barrel does not work like a conventional firearm, or even a conventional paintball gun barrel.  The flatline has a curve to put backspin on the ball.  The bore of a flatling barrel in not smooth like a normal barrel.  It is a little rough so the paintball gets friction from the barrel as it travels along the curve which puts the spin on the ball.  A larger paintball can contact the sides of the barrel interfering with the backspin you are trying to put on the ball.  Ideally a smaller paintball will only contact the top of the barrel as it travels through putting the proper backspin on the ball.

Also high fps will not make it shoot flatter.  Flatlines usually like around 270fps but every marker is different.

Just a FYI I have only been playing a couple months.  The information I have given is mostly from reading and talking to some experienced paintball players at the local arena and shop.

As far as a distance on accuracy, I never really measured.  Its pretty far though.  I have been planning on getting a rangefinder and chrono and really dialing in my marker.  Lately most of my playing has been arena ball where the longest shot is 50-100 feet.