This is also on tonight at 10 pm Eastern time. The channel was formerly the Military Channel. I've not read anything further about the series than what is posted here (and haven't yet checked out Ghis's link) but from the vague description posted on my cable, it's presumably about Wyatt Earp and Doc Holliday's going after the men who shot Wyatt's brothers, assassinating Morgan Earp and wounding Virgil Earp.
Fast is fine, but accuracy is everything. ~ Wyatt Earp