Whatever will run 100 rounds without any problems is the best ammo.

Not every ammo offering will work in every gun.

Hardball is most likely to work in any given gun.

Lots of folks are enamored of more expensive ammo marketed for sd, but precious few are willing to buy enough of it to actually run 100 rounds to establish reliability.

The most important quality for sd ammo is that it reliably run in YOUR gun, not my gun.