The problem of crime prevention in the sphere of illicit trafficking in weapons is a multidisciplinary one. The generalization of court practice in criminal cases connected with illicit trafficking in weapons in border regions has revealed some controversial issues. A scientific novelty of the research can be explained by the following: the lack of a scientific development of the issue related to the preparation of a state prosecutor for the above trials has predetermined the possibility of an integrated research of both theoretical and applicative problems of realization of the institution of court procedure and the development of some tactical recommendations. To be well prepared means for the prosecutor to examine the case, to coordinate the accusatory pleading in court taking into account the audience and to ensure the effective optimal participation in the case. The author has proposed the set of rules for the preparation of public prosecutors for participation in trials connected with illicit trafficking in weapons in the Prosecutor's Offices in the Republic of Tuva with his own additions. Some Prosecutor's Offices in the Republic of Tuva involve future public prosecutors into the work of operational groups investigating grievous crimes or serial grievous crimes. The author recommends the public prosecutor in the above cases the list of normative legal acts, decisions of the Constitutional Court of the Russian Federation and rulings of the Plenum of the Supreme Court of the Russian Federation. It is recommended for the prosecutors in Siberian federal border regions to draft plans for the preparation in criminal trials. The plan shall reflect: a crime event, evidentiary foundation completeness, revealed investigation deficiencies, the quantity and essence of possible motions, directions and sequence of examination of evidence, participation in investigative actions and overcoming of counteractions of defense. Besides, we recommend the prosecutor who either supervises the activity of preliminary investigation bodies or works closely with investigators and operative investigative bodies and has the information about the essence and special aspects of the case to support state prosecution. It enables to form a full and objective position of the prosecutor in a criminal case and to define the necessity of making a motion at this stage. Moreover, if a public prosecutor knows the materials of a criminal case and the process of their formation (the details of criminal investigation), he has the opportunity to state a more substantiated position as far as the motions of other parties to a trial are concerned.