Details on GSh-30-2K cannon

[Volk.]

Anyone have the specifics on the cannon?

By that I mean milliradian spread, recoil force, etc.

I've found some conflicting stuff on recoil and projectile+round weight (for the same type of shell), but never anything concrete on spread/dispersion, other than something that alluded to 1mrad, which seems like a selective result taken from the ground maybe.

Most sites just list 750 rounds as well... or show the Su-25 stats.

Edited August 22, 2021 by Volk.

[AeriaGloria]

It’s not in the LUA files, in the Mi-24P LUA it has a recoil coefficient described as .91, no idea what that means. Shell weight is described as 390 grams. Su-25 has same recoil coefficient, but perhaps it’s also tied to muzzle velocity and I can’t find that in LUAs anywhere, I know per most numbers the 2-30k has a 8% advantage in muzzle velocity over the 2-30.

There are multiple references in both LUAs to using the Gsh-30-1 shell, which is listed as having a 890 v0, which might be muzzle velocity as that’s close to the Gsh-30-1 900m/s muzzle velocity that’s often publicly listed. The Gsh-2-30 often having 870 m/s listed and the Gsh-2-30k having 940 m/s listed.

I believe the dispersion is listed as Da0 and Dv0, .0005 and .0081 respectively. You might be able to figure out what that is by looking at old GUA-8 and M-61 dispersion threads.

 

other then that Su-25 and Mi-24P both list it as Gsh_30_2 with identical specs, dispersion, muzzle velocity, recoil coefficient. Hopefully it’s WIP and the small differences are added. Here’s the LUA’s so you can check yourself https://github.com/Quaggles/dcs-lua-datamine/#table-references.  You want to check shells under the new weapons API section and helicopters or planes on the units section.

 

Granted units is suppossed to cover AI only, perhaps the player flyable modules are different, but all other LUAs for the guns match player aircraft, so who knows.

 

apocryphally I’ve heard 60kn of force for recoil, pretty crazy huh? 
 

I believe the value in DCS is multiplied by 8000 to get an 80% circle based on previous statements by Yo-Yo. That gives us a 4mil 80% dispersion for our gun Da0. 
 

from another post here “

• The Mirage is 0.0008
• the Harrier's gunpod is 0.0005
• the Mig-29/Su-27 is 0.0005
• the Su-25 and Su-25T are 0.0005
• the Mig-21 is 0.0007
• the Ka-50 is 0.0005 for HE and 0.0004 for AP”

 

for other reference GAu-8 is set to .0011 and M-61 is .0015 

 

Edited August 22, 2021 by AeriaGloria

[AeriaGloria]

 I found propellant weight from here http://www.russianammo.org/Russian_Ammunition_Page_30mm.html. This page also informs me that Gsh-30-1 use the same projectile(predictable I guess), and so that reference in LUA makes sense. But irrespective of gun says their muzzle velocity is 890 m/s. Considering this is a Russian site with data that was turned into a book, I wonder if this is either ED’s source or they use the same source. 

I tried using recoil calculators using the propellant weight and adding gun weight(what’s the difference when it’s all fixed?), and got .13 kN(for a short 10 round burst which sounds way to small) or the reverse of the force of a 390gram bullet at 890m/s(32.5kN, must be wayyyyyyyyy too high), so I don’t know. I’m very surprised LUA didn’t have recoil info, unless it’s the Dv0 of .0081 or “k1 =7.6e-09.”, or even round mass=.98. 
 

I doubt we’ll ever get an answer 

 

Edited August 23, 2021 by AeriaGloria

[Volk.]

Thanks. I have also seen that specific site. I didn't go delve in the Lua files, but can't remember if it was Kintex or which source, but one of the ammo stat pages did have meters deviation/spread for the 2A42 & GSh rounds which did seem to imply the GSh had slightly worse accuracy in that regard. But recoil numbers I see all over the place. Some say 30kn, others 65kn. Far more than the 600-ish kg recoil force from most other helo 30mms.