Home Forums Hunting & Shooting Ask The Gunwriters Undersized bullets question

Almost all bullets swell or obturate when the pressure increases against the base. The bullet base will deform or bulge, effectively sealing the bore. This happens quickly. The amount that the base will deform depends on the jacket thickness and the purity of the lead. Also, the length of the leade. After the case is pushed against the chamber, the slightly larger circumferential area of the leade allows the base to swell before it enters the rifled portion of the barrel.