Infinity, Stealth, KSC and many others are cheap and they have poor quality control. Therefore, many bbs differ in size and weight, and can be deformed.
Airsoft Elie, Excel, and Tsunami are the only kind of bbs that should be used IMO. Airsoft Elite BBs have performed better in quality control tests, such as diameter, weight, and roundness consistancy. Also, since they are a little bigger in diameter I assumed they would fit the inner barrel better. I only use AE. I also sell AE bbs. email me if ur interested.