So, how does Constant-Recoil actually work? In a sentence, it spreads the weapon's recoil impulse out over time. So, instead of the shooter receiving a sudden jolt to his shoulder, he receives a slow, constant push. The Ultimax utilizes a relatively long receiver length to accomplish this. The long receiver combined with recoil spring weight keeps the bolt carrier group from impacting the rear of the receiver when the weapon is fired. It's this impact that normally transfers most of the recoil impulse to the shooter, especially since it happens so quickly (over a very short period of time). In contrast, when the Ultimax is fired, the bolt carrier group runs out on the recoil spring, never making contact with the rear of the receiver. Then, as the bolt carrier group runs back forward, it impacts the barrel extension, knocking the weapon forward and causing the muzzle to dip, whereupon the next round is fired (We're firing on full-auto, remember?). So, as the weapon goes into recoil again, it has to overcome the weapon's forward momentum, as well as the barrel's downward movement, so half of the weapon's recoil forces are spent fighting against this forward movement, and then the bolt carrier group has to make the long trek towards the rear of the receiver, again. This whole process spreads the recoil force on the operator out over a greater period of time, making the weapon feel like its steadily pushing on the operator, instead of pounding against him. So, the weapon just sits there, staying on target during full-auto fire, even though it weighs so little.
The practical benefits of all this are huge. Believe it or not, Ultimax offers an 8:1 hit-ratio advantage over the M16 rifle when both are fired offhand on full-auto side by side against multiple targets, including moving targets. When both weapons are fired from the bi-pod, the Ultimax offers a 2.5:1 hit ratio advantage over the M16.
