The difficulty I found with the HW97 was establishing a suitable machined horizontal surface (i.e. a surface at right angles to the vertical axis of the gun) to enable the placing of a spirit level. Two methods I have thought of, although only the second one is safe: 1) cock the gun and leave it cocked to expose the parallel horizontal surfaces either side of the breach chamber, unsafe as it means messing around with a cocked gun. 2) obtain a small engineer's pin vice, clamping it (upside down) across the two machined vertical faces just before the breach chamber. Once clamped in position, the upturned face of the pin vice should provide a suitable horizontal surface for placing a spirit level (“gun level”). Once the gun level is in place, the arrangement can stay there during setting up to ensure verticality of the gun axis whilst the scope is lightly bolted down. The scope reticule should then be aligned against a known vertical, such as a wall. For the avoidance of cant, a miniature horizontal spirit level can be added to the top of the scope. Before final torquing up, the gun and scope levels should both be horizontal and the scope reticule vertical.
