context: In 1924, the Soviet military leadership decided to create a regimental cannon, since the 76-mm cannon arr. Introduced into the regimental artillery in 1924. 1902 was too heavy and limited. It was decided to abandon the design of the gun "from scratch", creating a gun based on existing samples. As prototypes were considered 76-mm mountain gun mod. 1909, 76-mm anti-storm gun arr. 1910 and 76 mm short cannon arr. 1913, of which the last was chosen at the beginning of 1925. The design task for the new gun was issued by the Design Bureau of the Arms and Artillery Trust (OAT) under the leadership of S. P. Shukalov, and designer Sokolov also presented his project [3]. The design of the new gun was completed by the end of 1925, at the beginning of 1926 a prototype gun of the KB OAT was made [1]. Testing of prototypes of guns was carried out at the Scientific research artillery range and the Klementyevsky range of the Leningrad military district from January to June 1927. During the tests, the inexpediency of increasing the initial velocity of more than 381 m / s was noted (at high speeds, gun instability and a large spread of shells were observed). Wishes were also expressed to increase the maximum elevation angle of the gun and the maximum speed of the wagon. After carrying out appropriate improvements, in early 1928 the gun of the design bureau of the OAT was adopted by the Red Army under the official name "76-mm regimental gun arr. 1927. " At the same time, all work on further improving the guns was assigned to the Artillery Technical Office (ATK) of the Putilov Plant, where the serial production of guns was started. Before the serial production of the ATK, under the leadership of F.F. Lender, it made some improvements to the gun. The first serial regimental guns were adopted by the military on December 22, 1928 [1].
question: Who was the designer of the 76-mm regimental gun of the 1927 model?
answers.text: Sokolov