44 Henry spherical. Henry also supervised a completely new rifle design based loosely over the Volcanic to employ The brand new ammunition, retaining only the general form of the breech system plus the tubular magazine. This became the Henry rifle of 1860, which was produced by the New Haven Arms https://highimpactrounds.com/product/winchester-xpert-20-ga-2-75in-6-3-4-oz-1325-fps-game-load-25-rd-box/