How does the Russian Shkas action work?

[OC_]

I was stumbling around and somehow found an article on Wikipedia about the Shkas machine gun. I knew nothing about the gun before that point, but it seems to be an interesting design. It uses a type of action I never heard of before called a 'Gas automatic revolver' or a gas operated revolver. It had a belt fed 10 round chamber drum, which I have a hard time picturing.. The gun had a high rate of fire at 1800 rounds per min, a later version of it was around 3000.

Does anyone know how this belt fed automatic revolver works?

http://en.wikipedia.org/wiki/ShKAS_machine_gun

 

[Detritus]

My assumption from the description would be that it operated in the same or a similar way as the US M39 20mm cannon which with 5 chambers had/has a cyclic rate of about 1,500rpm. Ammo is fed from a seperate drum or ammo box by feed belt/tray to a set of revolving chambers arranged very much like the cylinder of a revolver pistol. each round is fed into one of the chambers in the "cylinder", the "cylinder" performs in a manner exactly like those found in a handgun conveying the rounds to the breech of a single barrel and beyound where the spent cases are ejected and fresh ones take their place.

as the wiki for "revolver cannon" will state, the advantage of the design over it's major competition the Gattling-style gun is that while the revolver type cannot maintain as high a rate of sustained fire as a gatling type, due to its lower "revolving mass" it has a higher inital rate of fire, in other words it gets up to it's full rate of fire faster than a gattling type.

 

[OC_]

Thats a pretty cool looking cannon, i wonder how it loads and ejects each cartridge. Almost seems like it would have a special device just used for ejection thats not connected to the bolt.

 

[max popenker]

The basic action of the ShKAS is fairy simple - it has single barrel and conventional tilting bolt, operated by gas piston, more or less similar in concept and idea to ZB-26 or Bren
the trick is in the belt feed unit, which has a rotary sprocket which pulls the belt across, at the same time gradually pulling cartridges from the closed loop links rearward
This is required to slow down rearward movement of the cartridge, to avoid pulling bullets out of the case by inertia forces
In concept, ShKAS feed unit is also similar to one used in old Schwarzlose MG, although in ShKAS feed sprocket has more "teeth" for individual rounds, and is located differently

 

[Sam1911]

So what would the benefits be over the PK series? Strictly rate of fire, I assume?

 

[Ian]

Rate of fire was the advantage - it was intended for use in aircraft.

 

[EmbarkChief]

Very interesting! That explains a few things from a combat flight sim I used to play called IL2 Sturmovik that featured a few planes with this weapon. Those little MG’s fired so fast the green tracer’s looked like laser beams LOL. In the sim they were commonly used to act as “spotter” rounds for the bigger cannon’s in the ground attack aircraft and in the smaller planes like the I-16 and I-153 it was pretty handy for early war fighters.

 

[-v-]

Also, the ShKAS being a pre-WW2 design pre-dates the PK machine gun by almost 20 years.

 

[max popenker]

yep, the only advantage of the ShKAS was its high RoF - about 1800 RpM
It was very cool for mid-1930s, but by the start of WW2 most .30-ish caliber aircraft and AA weapons became obsolete due to evolution of combat aircraft