AGYG-----i am not going in to grat detail on some of this but here you go. BF -taking a bullite fired from the berral---taking a case fired from the chabmer.-----the bulliet would probly be the test fire for opperation. the riffleing leaves distant marks on bullet's. "right?". ok as the gun is shot,cleand or defaced on perpious--the rifling wears down some of the tooling marks wear down. the bf "rifleing marks" match the tool marks, twis rate and derction,and any other inperfections in the barral the origanal bullet taken for the BF will not match bullets fired later. when the riffling,tool marks,and inperfections wares down they no longer put the same riffling on the bullet. the constant is the twis rate and the rotation but that is the same in all most all guns made in that seris.ie( just using as and example say you buy a savge 110carbine in 30-06 the barral has its on induvisable marks that ware over time then it has the standerd twis "ie 1 turn in 12 1-12 right hand twist that is shared with all 30-06 savages 110 carbines not just yours." -------now it would take a lot of shoting or cleaing but it will change with time. there are spical coumpounds on the shoting market that pollishes the inperfections out of the berral on perpious.its sold to take the inperfections out to get better aceracy. the same thang to a lesser exstend is done when you brake in a new guns barral. with shoting and cleaning it takes out the ruff edges---------------------------------------------
now on to the cases when they expand in the chamber and aganst the bolt face. they leave markings on the case. cleaning again will put marks on the chamber if done inpropley----the chamber can be pollished to ade in fuction Ie make the chamber feed and extract better----this will also change the bf------the bolt face the same stuff applys plus-the prime has the firing pin marks and extractor marks the fp is relitive easy to replace and is commanly done to increas lock time. there are other thang that can be done on perpious just to change it. the extracter can be changed or modifey just as easy-------
Depending on modle of gun the barrals,bolts,fp,are easly and comanly changed. the stuff scince its replacment parts can be leagly sent through the mail----and it efectly is a new gun just on the old guns fram---------------
this stuff is done every day some of it is simmply done and does not need a gunsmith it can be done at home-----the gunsmits changes,reberrls,fine tunes actions every day all over the us------------
this stuff is not done millishely is coman for inproving guns,in fuction,relibalty,action,aceracy,experminting---------its extrmaly comman in compitision and spictly guns includding hunting guns-----so the BF is not perment by any means.....if you dont belive me look it up is comman in gun mags.
L. O. D. Charter member and L.O.S.
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