I know there are many ways to ensure your cross hairs are in line and true to the bore of your barrel. Level the rifle, hang a plumb line and align the crisshairs being the quickest and easiest way. This works very well on most rifles with a flat spot to use as a reference. Like on a break barrel, the breach block can be used. But what about a rifle without a level reference? Let's say a Tx200 or a HW97? I won't use the stock as a reference or use the scope base because I just don't trust these at all. so what does one do in this case? How did you do it??