The capital of the Siberian Khanate, the Isker hillfort, is located on the right bank of the Irtysh River, 17 km up from the mouth of the Tobol River. A large collection of bullets has been assembled on the monument, which were left by the soldiers who participated in the Yermak's campaign. For the first time, the data on 30 bullets from Isker were reviewed by A.P. Zykov in a joint monograph published in 2017, which included the bullets stored in Tobolsk Museum Reserve. However, some conclusions made by the researcher were not supported by the museum's collections. In total, 23 bullets are stored in the museum, and there are no bullets less than 8 mm in diameter, no bullets with a lead funnel, and no cylindrical bullets produced by cutting a lead rod into pieces. In total, our work made use of the data on 139 bullets that are stored in Tobolsk Museum Reserve and bullets that we found during the field research and collection of artefactual remains from the Isker hillfort since 2007. The bullets can be divided into two groups: molded (137 items) and mechanically manufactured (2 items). For the bullets, 12 variants of the traits, which characterize some features of their manufacture, and traces of impact on the projectiles before expulsion and those that appeared afterwards, were identified. During the manufacture, the bullet shape was attempted to be made spherical; this was recorded for 37.4 % of the items. Twenty-three percent of the bullets feature a seam from the mold sections, 14.4 % of the bullets preserved areas from lead shrinkage when cooling in the mold, 1.4 % of the bullets preserved a lead funnel, and 27.3 % of the bullets have notches made to increase their lethality. Furthermore, 58.3 % of the bullets bear traces of shooting — striation caused by friction of the projectile against the smooth barrel and traces of deformation caused by hitting a hard surface; only 10.1 % of the bullets are significantly undermolded or cut in halves. Summarizing the data on the bullets from the Isker hillfort, it must be noted that the Russian warrior host of 1582–1585 were armed with Russian-made muskets of small calibers of 8–15 mm. At the same time, the vast majority of them had a caliber of 10–14 mm, of which almost 2/3 were of a 12–13 mm caliber. The warriors campaigning in Siberia did not feel a noticeable shortage of ammunition, conducting annual target practice shooting at hard targets. Ball bullets were used, without lead funnels, which were cast from a precisely measured amount of lead. Notched bullets were quite widely used.