I have used both the 505 and the 510 for years. The 505 is faster, but the little fine adjustment weight can jump out of position when you remove the pan, so keep an eye on it. The slower to adjust 510 doesn't have that problem. The 505 is easier to find the weight of something such as the powder charge of a cartridge you broke down or a bullet.
Last edited by math teacher; July 20, 2012 at 02:21 PM.