Three more, and two images of a ca. 1550 Nuremberg arquebus with much the same lock mechanism; the latter are almost 30 years old, so please be tolerant.
At bottom, I enclosed some views of ca. 1566-1570's Styrian double-tinderlock mechanism (tillerlock and snapping tinderlock) calivers in the Landeszeughaus Graz; they all feature the downward bent petronel
buttstock the lower end of which was completely encompassed by the right hand and held in front of the arquebusier's breast when firing.