My friends used these all the time so I finally broke down a little over 6 months ago and bought a case. Great balls but they are small so you need a .687 or .685 depending on the batch of paint. Dead on accuracy and excellent marking. Sometimes the paint is extremely gooey if you get a real good batch. I nor my friends have ever had a barrel break with any xball paint. The only bad thing we had happen was we ran into a batch that the when shells broke they broke into shattered looking pieces. Not a big deal---Unless you get hit in the neck or hand. The paintballs still worked great it was just an unusual thing that created an unusual sting.
We used these until last month when our supplier couldn't get them from National Paintball anymore. If that wouldn't have happened we would still be using them.