The Red Army started WWII with two infantry machineguns: the light magazine fed handheld DP and heavy belt fed mounted Maxim. Both were quite aged designs by the time, so a replacement was considered. The GVG was one such replacement, eventually morphing beyond all recognition into the SG-43.
Photo #1. Magazine fed GVG machinegun in combat position (bipod with limiters)
Photo #2. View from the right. GVG machinegun in transport position.
"Photo #3. Belt fed GVG machinegun in combat position with rollers.
Photo #4. View from the left. Belt fed GVG machinegun in transport position."
Photo #4. View from the left. Belt fed GVG machinegun in transport position."
"Conclusions
Based on the results of trials, NIPSVO KA concludes the following:
Positive qualities of the machinegun
1. Simplicity and convenience of use (loading, clearing jams, moving firing positions with rollers, etc).
2. Simplicity and low cost compared to the DP machine gun.
3. Satisfactory shot groups, equivalent to the groups of the DP with the Starovoytov mount.
4. Two feeding mechanisms, belt and magazine (stock).
5. Reliability of the magazine feed, both with brass and steel casings (out of 4594 rounds fired, the machinegun caused jams 0.13% of the time), and the belt feed with steel casings (out of 16717 rounds fired, the machinegun caused jams 0.3% of the time).
6. Satisfactory life span of machinegun parts.
Negative qualities of the machinegun
1. Low reliability when using belt feed with brass casings due to bullets falling out.
2. The rate of fire with magazine feed is high for a hand-held machinegun (660-765 RPM).
3. Unreliable operation of the machinegun with an unevenly loaded belt (when rounds are loaded too deeply).
4. Small design flaws, unsatisfactory magazine latch, backplate pin, barrel retention wedge, etc.
Conclusions
Based on the above, NIPSVO KA decrees that:
1. Due to the sufficient simplicity of manufacture, ease of use, and combat quality of the machinegun (groups, parts lifespan, mechanism reliability), it is reasonable to produce several experimental prototypes for the final solution to the question of mass producing this machine gun.
2. When producing experimental prototypes, resolve the aforementioned defects."