ball-bearing i thought it was a size comparision. there a b and bbb sized balls. BB guns shoot small BBS that are normally .177 caliber (4.5mm). a bb is a ball bearing that the gun shoots. the speeds...
If you have the money, someone will do it.--------------------Do a search on the web for "airgun repair" and locate someone near you that repairs airguns.
Both are about the same it all depends on what you want to use it for. If you want to know more about BB/pellet gun systems then read my profile on the ***Air Gunning section***** See the link below.