i have a stock barrell and nothing is wrong with it yet
Strengths:
Not much. In my gun they rarely broke.
Weaknesses:
I bought them from a dealer and they were expensive. My friends were using a Viewloader Genesis and a Pirahana G3. The balls broke in their guns about every 50 shots. They broke in the speedloaders, and our hoppers. Very unaccurate.
Conclusion:
Don't waste your money on these balls. Your better off with Brass Eagle.