Hybrid airsoft guns originally debuted in the middle of 2006, although they have not become very popular since. This new type of airsoft gun functions differently from gas, electric, and spring airsoft guns (although it is powered electrically). In fact, it works almost exactly like a real gun. BBs are placed in the front of real-like shells, and red caps placed in the back. The shells are inserted into the magazine, and the magazine can be loaded regularly. After pulling the trigger, the firing pin in the 7.62×39 hunting ammo gun hits the red cap on the back of the shell, which explodes and creates a high pressure inside the casing. This pressure pushes the BB out through the barrel at a velocity which is unachievable by the other three types of airsoft guns.
Real guns operate very similarly, in that the firing pin strikes the primer, creates a spark, and ignites the gunpowder. The burning of the gunpowder creates gas and pressure inside the shell, which pushes the bullet out. The differences between the real gun way and the airsoft gun way is that only a tiny amount of gunpowder is used in the red caps for airsoft (while a lot is used in real shells), and the pressure created in an actual gun is much higher than in an airsoft gun (also, there is the key difference of the projectile being metal instead of plastic).
With a hybrid gun, you obviously need to be much more conservative with your shooting, or if you feel the need to fire a great deal, you must take a lot of time to prepare more rounds. That is the clear negative of hybrid guns; the need to prepare each round (or you could probably buy rounds pre-assembled, but they will of course be more expensive than regular BBs). However, there are positives. For one, many players will be attracted because of the stunning realism, as now not only does the gun look real, but so does the ammunition. As stated, because of the nature of the ammo, the velocity achieved is very high. This is great for snipers, who now can shoot from much further back (higher speed = more distance). In fact, hybrid guns would be good for many single shot airsoft models, although using one in a semi-automatic or fully automatic model would result in paying a lot of money or using a lot of time for the ammunition.