I compete in USPSA.
When using revolvers I've competed with 4" GP100s, 5.5" Redhawks in 41 and 44 Magnum, and 45 Colt, and a 7.5" Redhawk in 357 Magnum.
I draw the GPs from a very old Ernie Hill holster, and the Redhawks all get/got drawn from a custom Milt Sparks HSR .
I use HKS speedloaders exclusively.
I haven't 'shot revolver' since strong-side injuries in the mid-2000s, but I think I'll be trying again come next warm weather ('cause when it's really cold and snowy the speedloaders get froze up after hitting the ground and it's just a complete pain to warm them up enough for reuse).