Depends on the range to the target. Due to the Fast Cav rules and Quick to Fire Ability of the pistols they only suffer the Multiple Shots penalty and range penalty. Of course there may be some cover penalties if the target has any.
If range to target is under 6" and they will hit on 5+. If range to target is 6" to 12" they will hit on 6+.
Of course if there is an Outrider in the unit, he will hit on 4+ under 6", and 5+ at 6" to 12"