The 9x39mm Grom is a Russian round that was designed in 1980s to be used as a subsonic round for the Russian special forces.
The round can be made using high quality 7.62x39mm (M43) brass that has been resized (re-necked) up to accommodate the the 9mm projectile
The 9x39mm Grom is used for silent operations at up to 400 meters (440 yards)
Russia has denied export of the 9x39mm Grom to the U.S. causing owners of weapons that fire this in the U.S. to have resize brass and manufacture the round stateside.
From what I have read the most common rounds to be used in suppressed (silenced) weapons are the 9mm and the .45ACP when the SP-5 9x39mm is compared the SP-5 gave twice the muzzle energy and 3 times the effective range. This round is a short range (400 meters) for both Snipers and as an assault rifle
The SP-5 also has designed in the projectile an air pocket in the tip of the round to start tumbling (yawing) so it will cause more damage to the target rather then a small “pencil-like hole” that the 7.62x39mm round more commonly will do when entering a target.
Partial list of weapons chambered in 9x39mm Grom
- OTs-12 Tiss
- OTs-14-4A Groza
- SR-3, SR-3M Vihr