What's so radically different about this one?
It's probably the only AK besides AN-94 that hates dirt...that's only thing radical about it
When a gun is fired you feel two different kind of force. First as soon as the primer gets ignited you feel a strong but dull force that's basically the momentum of firing a gun; mv of bullet gets balanced by MV of gun. Then at last you feel a weak but sharp impulse and it's the whole BCG coming to a stop at the back of the receiver by transferring it's KE to your shoulder. These two different forces are clubbed together and is colloquially called recoil.
Except one system all other systems try to deal with that second part of the recoil; BCG slamming into your shoulder. You can use rubber buffer at the least, some uses hydraulic dampeners, as
@Corvus Splendens pointed about the constant recoil systems which slowly drives down the v out of ½mv² to zero before the BCG gets a chance to slam at the back of the receiver (v=0 means whole KE=0) or you can use something like this, what's the Russians called balanced action...BCG moves rewards and a separate reciprocating group moves forwards with the same kinetic energy; effectively counteracting each other.
But end of the all these just deal with the smaller second force not the first one and it's the first one that's significant. And there's only one way of dealing with it and making a gun truly recoilless...by vectoring gases in the opposite direction of the bullet. When the angle of vectored gases and the bullet is 90° you'll get 0% recoil reduction and when it's 180° you'd get 100%; something that happens in recoilless launchers. But the more this angle is from 90° the more gases would be re-directed towards you resulting in muzzle blast and concussion so a compromise is done and generally the angle in muzzle brakes are around 135°.
So TLDR; all these contraption do reduce recoil but it's not that significant and comes at the cost of being complicated, susceptible to dirt and slower RPM.
A muzzle brake on the other hand is just one solid piece of steel that can reduce as much as 60% of the recoil with the only drawback being slightly high muzzle back blast.
www.andres-industries.de
defenceforumindia.com
