 If the stock is manufactured from wood, environmental conditions or operational use may warp the wood, which may cause the barrel to shift its alignment slightly over time as well, altering the projectile's external ballistics and point of impact.Contact between the barrel and the stock also interferes with the natural frequency of the barrel, which can have a detrimental effect on accuracy especially when the barrel gets hot with repeated firing.The interference of the stock with the barrel's oscillation harmonics as the bullet passes down the bore can cause the barrel to vibrate inconsistently from shot to shot, depending on the external forces acting upon the stock at the time of the shot.