Tarantino loved this movie, loved Robert Culp in it especially, and "homage" the Culp/Welch gunfighter tutorials with the master/student swordfight tutorials in Kill Bill.
It was rebooted as "6 Guns" (2010) and is about on par, but people dismiss it because it's an Asylum production https://www.imdb.com/title/tt1558576/?ref_=nv_sr_srsg_0. I think it might be slightly better than "Hannie Caulder" if for no other reason than the villains are less hammy.
The next remake will take place in modern times in Detroit. A gang of evil, white, red MAGA hat-wearing Trump voters will attack Hammie Caulder, a gay black man played by Jussie Smollett, rape him and kill his husband and their whole family. Babies, too this time. Jussie will seek out the Master Gang-Banger, played by Samuel L. Jackson, who will train him to be a professional killer, wiping out dozens of evil white Republicans using submachineguns wielded in the Gangsta sideways grip. Rap score by Li'l Wayne.