Don't know about the specific unit, but the most common .58s were the US 1861/63 Springfield and the British p1853 Enfield (actually, .577, but the rounds were interchangeable). Both were, are, sophisticated, accurate rifled muskets. The Enfield had a better sight, but troops commonly knocked it off and sighted along the barrel. Some soldiers liked the sling placement of the Springfield better, since the weapon rode higher.
Where did the 30th serve?