„The threading shown in this clip is made on a barrel of recognized quality, in which the bore is both straight and concentric. However it is correct that there are barrels of lesser quality and manufacture, in which the bore may be excentric, and occasionally even slightly curved. These barrels are controlled and centerede prior to threading. Furtheremore, all barrels are visually inspected after the threading. Concentricity (or excentricity) can, with experience, be determined by looking through the bore. It is worth mentioning that less than 1 in 100 barrels are so poorly centerede that they require adjustment. These statements, and the statistics, are based on well beyond 3000 mountings of rifles of varying manufacturer and quality. As an added safety precaution, the diameter of the internal hole of the silencer is made 1 mm larger than the diameter of the caliber for which it is sold. Thus even if the bore should be excentric in such a slight degree that it is not apparently visible, the added diameter will allow for the projectile to clear the silencer. Thank you for pointing this out for clarification. „