Welcome.

First off, what do you mean by "straight"?  Paintball guns are never as accurate as real guns - there will always be accuracy issues.

But if your balls are veering wildly off to the side, you may have broken a ball inside your barrel, which will kill accuracy.  Always carry a squeegee and keep your barrel clean.

If it is just a matter of shooting kind of straight, but not straight enough for your liking, there are many things you can do to improve accuracy.

First, better paint.  Big Ball is mediocre paint at best.  PMI Premium (for instance) will show improvement.

Then, a better barrel.  The stock 98 barrel is not great.  There are variety of aftermarket barrels that will improve performance.

And so on...   welcome to upgrading!

:)

I suggest like baratak said looking into a freak set if you use different types but if you are willing and able to always have the same type look into the flatline. An amazing barrel adding an extra 100ft or so with much more accuracy. 

But like the other guys said balls are a major problem. B/c of their flexibilty or weakness they can go ne which way at high speels like it a bullet was missing a chunk out of it or dented.  I find that if you buy better balls this isn't such a problemm along with fitting your balls o your barrel.

Yeah, first make sure the barrel is clean. Then check the velocity. If the velocity is turned up real high the balls won't shoot straight. If that doesn't work try using a different kind of paint. The bottom line is that for any of the 98 s the first upgrade you want is a new barrel because the stock barrel is pretty awful. As for what barrel, I'd suggest looking into the J&J Ceramic, Lapco Bigshot, Flatline, or like Baratak said look into a barrel set.

side note: CO2 can cause consistancy problems. You may want to look into that in the future.

Edit: I hope that helps. Welcome to the forums.

triggerfinger91 wrote: I just got my new 98c.  the gun is all stock.  it is running on CO2 and the paint in using now is the RPS Big ball.  When i first played i noticed that the balls weren't flying staright.  The day was cold and windy but not to windy.  can i get some help on how to fix this problem

Well, let's get some terminology straight first. The paint was visibly curving left, right, up or down? Or, you just couldn't hit your target due to inaccuracy...slight variations away from point of aim?

Wild curving with a occasional spiral curve is contamination in the barrel from a broken ball or oil or some other substance impacting the uniformity of the inside of the barrel.

Inaccuracy, slight variation in the point of impact, is most likely a mismatch of bore diameter and the paintball diameter. It can also be caused by quality of the paint...out of round, high seams, dimples from long storage (WalMart paint?).

Then there is always the wind, no matter how slight you think the breeze it will noticeably push the ball off target. If your paint curves slightly in the same direction shot after shot then there is probably more wind than you think.

New barrel - definitely.

Also, don't hold your marker with the barrel tip down while using CO2. The liquid CO2 flows into your marker and can really cause nasty fluctuations in the way the balls fly. The CO2 needs to have a chance to change to a gas form for better consistency.

An expansion chamber helps also. Make a habit of not dropping your muzzle.

Take off the barrel and drop a paintball into it from the back and see what happens. If it drops right through then the balls are too small. You should have to blow the paintball through the barrel with a little force. Then you are closer to the right size balls. Good luck.