LOL.....it's Hollywood. The truth is an after thought. Doc never used a holster when in Tombstone and Wyatt never carried a Buntline either. Ringo was no "gunfighter" as we know them from Hollywood. There were few (if any) "quick draw" type shoot outs at all. You shot gunned them on a dark street or shot them through a pool hall window. So pistol barrel length would not be that big of issue for any of them, except BP seems to prefer a longer barrel.