"hows a rainbow made? how does the posi trac rear end on a plymouth work? it just does" LOL i truly dont know. id have to do some research.
im gonna go out on a limb and say that nessecity was the mother of invention again in the fact that some of the first "pro shops" so to speak were gunsmiths at first were measuring this way any how?
"please join the N.R.A. as well as your state rifle association! these are critical times for ALL gun owners. Be informed, be active and stay vigilant"