More than likely, your velocity is fluctuating with your Tippmann... Do you have access to a chrono? Even the cheap handhelds will work, you want to fire about 10 shots over a chrono and see what your readings are. Most likely you need to do some maintenance to your 98 first. Once you have it polished, and the orings replaced, as well as lightly oiling your power tube, and set your velocity to 280 fps max (and that is assuming you are playing above freezing. When it drops below freezing you want to go down even lower with your velocity, I run about 250 fps when it is 20 below freezing (F) as since you are in southern Ohio like me, you have probably been shooting out in the cold.
Infinity is a pretty hard shelled paint, so it should shoot fine. I used it a few years ago for a season, and never had any breaking in the barrel problems, unless I tried to underbore in the cold... Then as others have said, you will break paint! You want a larger bore barrel when playing in the cold, as the paint gets more brittle the colder it is...
Most likely your problem was the "oily" paint was coating your barrel with oil, which caused resistance as the ball tried to fire through it, and with the paint being brittle, it was breaking.. Once you broke one, then you kept breaking paint...
Better paint, problem goes away!
But, it could also be fluctuations in velocity, so get your marker working perfect, clean your barrel until it shines inside, and keep all your insides clean (hopper, breech, ect) you don't want any paint/oil in there coating stuff.
If I have paint that is oily, I lay out a towel and run handfuls through rolling them around to pick up all the excess oil until it is all cleaned off before it ever gets in my pods, or gun!
Paint is by far the single most important thing you buy when playing the game, good paint is SO MUCH FUN, and bad paint will ruin your day!