GarryB wrote:That is rather unusual... when I first looked at it I thought it was the 2A42 cannon from the BMP-2 as the muzzle brake looks similar, but the barrel is rather too short and the mechanism doesn't look right where it enters the turret.
My guess based on barrel diameter and barrel length is that it is a 12.7mm HMG with a new muzzle brake, though it could be 14.5mm or perhaps even a 23mm calibre KPVB with an improved muzzle brake.
(Note the KPVB uses the KPV HMG design but replaces the 14.5x114mm HMG cartridge with a very similar 23x115mm round often used in Soviet aircraft including the latest model Hind with a twin barrel 23mm gun in a chin turret... the round designed to deliver a heavy (for its calibre) HE projectile at relatively low velocity (about 700m/s) but with compact ammo of low recoil at very high rate of fire... so instead of using very high velocity to hit small fast moving targets it uses high rate of fire bursts like a shotgun blast to pepper the area with projectiles... but with a light cheap low recoiling round that can be carried in large numbers because of its small cartridge case size... it is really the size of HMG ammo...)
If it is not KPVB, I would suspect it was Kord with a new muzzle brake.
Those smoke grenade launcher tubes are about 82mm in diameter, and the gun barrel near the muzzle is about 1/3rd the width... so that is is less than 30mm... and that is the outside of the barrel, so the calibre is likely 12.7mm, because whatever the barrel thickness is, you have to double it, to work out the width of the hole down the middle... at about 28mm that would be less than 4mm thick if it was a 23mm gun, so I suspect it is a 12.7mm calibre gun which means the barrel diameter is about 7.6mm thick... which sounds about right.
I really don't think it is a 30mm or 40mm grenade launcher... mainly because they are not high velocity rounds so the benefit of having a muzzle break is not that good.
A grenade launcher would be a fairly low recoil system in a vehicle turret.
Also the box on the side looks like the ammo boxes they have for 12.7mm MGs... in terms of depth and width.
Forgot to thank you for the input on this GarryB, so thanks anyway.
Little update on that photo : According to VitalyK, the weapon system is called "AP-23", so i assume it is supposedly a 23mm weapon system.
It has to be a 23x115mm system. Given the AP-23 designation, i assume the weapon is a modernized AM-23 cannon.
Overall dimensions seem to match based on what we can see in the photograph. As you pointed out, compared to the Kord, the original AM-23 has a bigger, lower velocity round with more HE power, and a higher rate of fire.
Alternatively, it could be a single barrel version of the GSh-23 which is chambered in the same caliber, but this to me at least seems less likely.
It could also be a modernized version of the 23x152mm 2A14 cannon, but i doubt this as well because it is not bulky enough and does not match the profile.
Or it is just a 12.7mm with a weird and confusing name.
A few things of note : Based on this picture at least, the gun seems to be integrated in an unmodified variant of ARBALET RCWS, utilizing the same ammo box and feeding ramp as the version using the 12.7mm 6P49/ 6P50. The 23x115 is obviously a larger round. Ammunition capacity would decrease by 50% ( around 200-220 rounds of ready to fire ammo ). For the weapon system to be more effective and utilize the inherent rate of fire, it would make more sense to increase the ammunition capacity. I am also not 100% sure if the feeding ramp would be suitable for the bigger rounds, though it is hard to tell based on a few pictures. It might not be a problem at all.
I tried to find some info on the Tula website and some other sites, but i could not find anything further about the weapon system after a quick search.
The weirdest thing if it is indeed a modernized AM-23, is that AFAIK the army has never used this caliber, only the VVS. I am also unaware of any export potential to nations who use the weapon in the ground to ground attack role. I cant imagine the army introducing suddenly a new caliber, so i doubt we will see much of this in the future.
Interesting concept however ! It could be very useful on a BMPT type vehicle. IMHO it can be usefull both as a co-axial weapon, or as a roof mounted weapon capable of engaging both drones and soft ground targets.
Would be interesting to see what types of ammo are available.