SVT -40 was a more refined, lighter design incorporating a modified magazine release. The handguard was now single-piece and the cleaning rod was housed under the barrel. Other changes were made in an effort to simplify manufacture. Production of this improved weapon began in July 1940 at Tula, and later at factories in Izhevsk and Kovrov. Production of the Mosin–Nagant M1891/30 bolt-action rifle continued, remaining the standard-issue rifle to Red Army troops, with the SVT-40 more often issued to non-commissioned officers. Since these factories already had experience manufacturing the SVT-38, production geared up quickly and an estimated 70,000 SVT-40s were produced in 1940.
By the time the German invasion began in June 1941, the SVT-40 was already in widespread use by the Red Army. In a Soviet infantry division’s table of organization and equipment, one-third of rifles were supposed to be SVTs, although in practice this ratio was seldom achieved. The first months of the war were disastrous for the Soviet Union, and hundreds of thousands of SVT-40s were lost. To make up for this, production of the Mosin-Nagant rifles was reintroduced. In contrast, the SVT was more difficult to manufacture, and troops with only rudimentary training had difficulty maintaining it. In addition,submachine guns like the PPSh-41 had proven their value as simple, cheap, and effective weapons to supplement infantry firepower.
This led to a gradual decline in SVT production. In 1941, over a million SVTs were produced, but in 1942 Ishevsk arsenal was ordered to cease SVT production and switch back to the Mosin-Nagant 91/30. Only 264,000 SVTs were manufactured in 1942, and production continued to diminish until the order to cease production was finally given in January 1945. Total production of the SVT-38/40 was 5,772,085 rifles, of which 51,710 were the SVT-40 sniper variant.
In service, SVTs frequently suffered from vertical shot dispersion. Many rifles were poorly seated in their stocks allowing the receiver to shift upon firing, though selective shimming with birch chips was practiced as a field modification. For a sniper rifle, this was unacceptable, and production of the specialized sniper variant of the SVT was terminated in 1942. At the same time, the milling of scope rails in the receivers of standard SVT rifles was also discontinued. Other production changes included a new, simpler muzzle brake design.
To supplement the Red Army’s shortage of machine guns, an SVT version capable of full-automatic fire was produced in 1943, and was designated the AVT-40. It was externally similar to the SVT, but its modified safety also acted as a fire selector. A larger 15 or 20 round capacity magazine was reportedly designed for use with the AVT, but this is unconfirmed and there are no known examples. The AVT featured a slightly stouter stock; surplus AVT stocks were later used on refurbished SVTs. In service, the AVT proved to be a disappointment: automatic fire was largely uncontrollable, and the rifles often suffered breakages under the increased strain.
The use of the AVT’s automatic fire mode was subsequently prohibited, and production of the rifle was relatively brief. A shorter carbine version (sometimes called SKT-40) was designed in 1940 and was reportedly produced in small numbers; but again, this is somewhat disputed. As a field modification, standard SVT’s were sometimes modified into a carbine configuration, with varying degrees of success and work quality. A prototype version chambered for the new, shorter 7.62x39mm round was developed, but was not accepted for production.