The picture of the towed Sosna-R that I had attached above is a version of Sosna with a twin-barrel 30 mm gun and 4 missiles which is a direct replacement for ZU-23-2.
It has been marketed as a replacement, which is not to say it will be selected.
They have upgraded the trailer...:
I know I am not continuing with my posts in an organized manner, but for whatever it's worth, I should mention that Russia is obviously not going to introduce any new systems that use the 23X152B rounds used by ZSU-23-4 and ZU-23-2. This round is going to get retired.
I agree, but what are they going to do with the 14.5m HMGs?
One option would be to keep them for APCs and light vehicles, but another option could be to rebarrel them to 23mm calibre and use the 23 x 115mm round used on the Mi-35M, which is a similar length to the 14.5mm HMG round but has a larger calibre for more HE weight.
A dual belt feed model of the KPV/KPB would allow HE rounds and AP rounds to be separated. With modern external mounts and aiming systems they could develop APFSDS rounds with rather decent if not exceptional performance in such a round so dual feed would offer compact powerful weapons with decent AP and HE performance in a low recoil compact weapon and compact ammo.
I think they talk about this towed Sosna gun/missile complex in nineties, but there are no words about it for very long time, so it is well possible, that this complex is canceled.
The towed mount shown in the photo above is slightly different.. with a more solid base. It would certainly offer a serious improvement for air defence forces in the VDV as the 10km range for SOSNA-R would be a large improvement over Strela-10M and any MANPADS. The maiin question would be do you go with the 30mm twin barrel cannon or go for double the missile load instead?
If 57mm guided shells can hit targets 16km away then the 2A38M twin barrel cannon might be a dead end... withdrawing it and the 23 x 152mm rounds from the ZU-23 weapons and replacing the 14.5 x 114mm HMG rounds with the 23 x 115m rounds used on helos (Hind) they might be able to replace the 30mm all together on the ground.. the Hokum and Havoc will use it of course, as will the Su-25SM3.
Perhaps a smaller lighter 23mm twin barrel gun for the helos and a 57mm gun for the Frogfoot and 23mm guns replacing 14.5mm... both a single barrel for coaxial use with heavier guns like 125mm or 120mm, and twin barrel for short range firepower vehicles like BMPT, while single barrel for APCs and commanders cupola guns... with IFVs armed with high velocity 57mm guns and ATGMs and air defence vehicles with 57mm guns and anti aircraft missiles...
With 2 twin barrel GSh-23 and 2 x 6 missiles, it could be too heavy for VDV use, but maybe 2 GSH-23 + 4 or 8 ( 2 x 2 or 2 x 4) missiles. It will be still very potent complex for VDV as well as for naval infantry.
GSh-23L is lighter than the four barrel 50 cal on the Hind... at 50.5kg each you could fit two guns for the weight of the twin 30mm cannon on the Hind or Su-25... which are light guns too.
Most importantly the low velocity means moderate recoil and larger ammo capacity.
If you think 50kgs per gun is too heavy a modified 14.5mm KPV HMG called KPB has been adapted to 23 x 115mm AFAIK and would weigh half as much again...
I think Sosna-M could look great on Kamaz-63969 Typhoon for light brigades.
It would be a very cheap but very potent weapon...