Heres the deal. When I went paintballing in Movember, I got one kill because my stock barrel for my Tippman A5 wasnt cutting it. (I was only killed once as well so its not me.) I looked into it and asked some pros at RAP4 the difference a flatline barrel and rifled barrel. I wasnt sure because of the price difference.
I got a 14 inch rifled barrel and never test fired it or shot targets, The first 2 rounds we played was 2 on 2 which I ended with 4 kills, 2 of them were headshots. It was at medium range and on the first shot at their current positions. Awesome barrel, worth the money.
The Real Action Paintball 14 inch rifled barrel is newer, so it should be commonly available, both new and used.
I bought this barrel needing a replacement for the stock one which was horrible. I have the non-quiet version and it is loud compared to others. The "rifling" in this barrel is not spiral but straight lines that run down the inside of barrel. Supposedly this creates less friction on the ball allowing it to travel down the barrel as fast as possible. It is also intended to PREVENT spin. This stabilization somehow helps the balls flight path. After installing it I instantly saw a performance increase. At close ranges this barrel has ball on ball accuracy. At longer ranges I would say it is relatively accurate although I'm sure there are better barrels out there. I would not recommend it for speedball due to the length, but it works great in the woods.
Overall it's nothing revolutionary, however, it does have it's benefits. If you're looking for a barrel to replace the stock Tippmann barrel and are on a budget than this is a great product.