In July 1940, a shot silencer called SG-42 (a 1942 special silencer) was tested at the NIPSVO, designed to fire a DP machine gun with reduced-charge cartridges. The tested SG-42 device, built on the same principle as the Bramit device, provided satisfactory jamming of the sound of a shot and was recommended for army supplies. At the same time, instructions were given about the need to refine the SG-42 device in order to eliminate a number of disadvantages (circular pitching of the device at the junction with the barrel, insufficient fastening strength of the rear obturator, the impossibility of automatic firing with the device without obturators with cartridges with a normal charge, etc.).
Sample 12/9. The SG-42 device is a modified design, mounted on a 7.62 mm DP light machine gun. OGK. 1942.
At the end of 1942, the SG-42 device was tested with an internal nozzle diameter reduced from 16 to 14.5 mm. This change, made in order to ensure the operation of the automatic machine gun when firing with a device without obturators with cartridges with a normal charge, showed positive results.
The design changes of the SG-42 device were as follows:
• in order to mount and disassemble the device on the barrel of a machine gun, the method of attaching the piston chamber of the device to the gas chamber of the barrel was changed;
• in order to reduce the number of parts, simplify the assembly and disassembly of the device, as well as reduce
the complexity of manufacturing, a fiber shock absorber (tip) was introduced stock;
The SG-42 device of the modified design has five fewer parts than the device of the old
design.
The main characteristics of the device:
• weight of the device 1,150 kg;
the total length of the device…291 mm;
length of the expansion chamber 98 mm;
nozzle length 85 mm.
Based on the tests carried out, the NIPSO noted that:
• The introduction of a fiber-tipped shock absorber deserves attention;
• the introduction of a shaped nut instead of a coupling did not solve the issue of maintaining the stability of the machine gun’s combat after assembly and disassembly of the device. The correctness of the assembly must be checked by shooting;
• The aiming scale previously proposed by the NIPSO must be applied to the instrument.
The main performers of the work: A.M. Marantsev and I. V. Dolgushev.
Source: inv. No. 52 F. 1301-1304; No. 675.16-1; No. 851.