The M-31UK rocket differed from the M-31 high-explosive projectile in its design mainly due to its oblique plumage and four special nipples 1 in the head part of the rocket chamber. The connectors were located near the center of gravity of the projectile in one plane perpendicular to the projectile axis, at an angle of 90° to each other. Inside each connection (see diagram) there was a channel with an external exit hole drilled at an angle of 90° to the longitudinal axis of the connection.
When the gunpowder charge was burning, some of the gunpowder gases, flowing out of the outer holes of the connectors, formed a reactive force, which rotated the projectile around its longitudinal axis. Thanks to this, the heap of M-31UK shells was much better than the heap of M-31 shells.
To seal the chamber, cardboard dishes were inserted into the outlet holes of the nozzles on varnish.
The M-31-UK also differed from the M-31 because the diameter of its critical nozzle was smaller.
| Caliber, mm | 300 | |
| Stabilizer wingspan, mm | 300 | |
| Full projectile length (without fuse), mm | 1760 | |
| Weight of final projectile, kg | 94,8 | |
| Header type | blast | |
| Weight of rigged head end, kg | 52,4 | |
| Weight of explosive charge, kg | 28,9 | |
| Weight of the rocket part, kg | 42 | |
| Powder charge weight, kg | 11,25 | |
| Fuse | GVMZ | |
| Resistance of incandescent bridge of electric ignition, Ohm | 1,0-1,4 | |
| The current needed to ignite the igniter, A. | not less than 0.5 | |
| Ballistics data | ||
| Rocket charge burning time, s | 0,9 | |
| Average reactive force, kg | 2500 | |
| Muzzle velocity of the projectile, m/s | 35 | |
| The length of the active section of the trajectory, m | 115 | |
| Highest projectile speed, m/s. | 245 | |
| The longest range of fire, m. | 4000 | |