Although set in the years just after the Mexican War (1846-47) the US Army soldiers wore uniforms and equipment that weren't standard-issue until late in the Civil War (1861-65)--repeating rifles, breech-loading six-shooters, etc. The Mexican soldiers, however, appear to have the correct uniforms and equipment for the period.
Although called "Raiders of Old California", it was set in the Texas/New Mexico area.
The marshal is being chased by several Comanches. He falls off his horse and rolls down a hill, losing his gun. One follows him on foot. They fight. He prevails. The next scene he's in finds him back on his horse with his gun. No explanation for how he got away from the rest of the Comanches and recovered his horse and pistol.