The public security organs have special regulations on the identification of guns. The Provisions on the Performance Appraisal of Firearms and Ammunition Involved in a Case by Public Security Organs are formulated to standardize the appraisal of firearms and ammunition involved in a case and ensure that the appraisal is legal, accurate and fair. First, the scope of identification. These Provisions shall apply to the public security organs that need to identify the performance of guns and ammunition involved in handling criminal cases involving guns. The standard guns and ammunition mentioned in these Provisions refers to all kinds of guns and ammunition produced by legal enterprises in accordance with the national standards or the tactical and technical indicators issued by the Ministry of Public Security and the army, and approved by the relevant state departments or the army, including all kinds of old miscellaneous guns and ammunition made abroad and left over from history. The term "non-standard guns and ammunition" as mentioned in these Provisions refers to all kinds of guns and ammunition that have not been approved by the relevant departments or do not meet the national standards, including self-made and restructured guns and ammunition and intermediate products in the development of gun and ammunition production enterprises. Second, the appraisal organ. The appraisal of guns and ammunition involved in the case shall be the responsibility of the local (city) level public security organs, and if the parties concerned or the case-handling organs have objections, the provincial public security organs shall re-examine it once. All localities may entrust the existing criminal technical appraisal departments of public security organs to carry out the appraisal of firearms and ammunition. Third, the appraisal standard. (a) all standard guns and ammunition, regardless of whether they can complete the firing action, shall be identified as guns and ammunition. (2) All non-standard guns (including self-made and modified guns) capable of firing standard ammunition shall be deemed as guns. Non-standard guns that can be loaded with standard ammunition, but cannot be fired due to lack of individual parts or corrosion, and can be fired after adding relevant parts or derusting are all recognized as guns. (3) Non-standard guns that can't fire standard ammunition shall be deemed as guns according to the Criterion for Forensic Scientific Appraisal of Guns' Injuries (GA/T), when the muzzle specific kinetic energy of the shot is greater than or equal to 1.8 Joules/cm2. (4) Special spare parts (parts) for standard guns and ammunition, which can be provided with drawings (copies) and part numbers of relevant parts by the manufacturer, shall be deemed as gun and ammunition spare parts (parts). (5) Parts (parts) of non-standard guns and ammunition that have the same functions as parts (parts) special for standard guns and ammunition shall be deemed as parts (parts) of guns and ammunition. Fourth, the appraisal procedure. The appraisal of firearms and ammunition should go through two steps: appraisal and recheck, and should be carried out by different personnel respectively. The reviewer shall conduct a review in accordance with the whole process of the appraisal operation flow to prevent the occurrence of wrong appraisal. After the appraisal is completed, a Certificate of Appraisal of Firearms and Ammunition shall be made. The appraisal conclusion in the Appraisal Certificate of Firearms and Ammunition shall be accurate and concise, and at the same time, the identities of appraisers and reviewers shall be marked with their own signatures and stamped with the seal of the appraisal unit. "Guns and ammunition appraisal book" should be attached with samples, sample photos and other accessories. 5. Time limit for appraisal. General appraisal and re-inspection shall be completed within fifteen days. If the problem is complicated, it shall be completed within thirty days.