A link that is still notably missing.
Also the Hop-up is based on backspin stabilisation, which was in use over 2000 years ago. The only reason it's called hop-up is the projectiles are now so light the backspin causes enough lift to briefly overcome gravity when the forward momentum falls below a certain threshold allowing the projectile to rise slightly about 3/4 of the way through it's flight before falling onto target.
When using very low muzzle energy the biggest restriction is the distance the shot travels, backspin more than doubles the maximum range you can achieve. If range was not the biggest issue we would see rifled airsoft with accuracy comparable to cheap airguns.
Still not found the link in question and I'm not wasting any more time looking at the weekend warriors shouting about how awesome little plastic balls are. I played with airsoft when i was about 10, I moved on. I still have three airsoft pistols all rated around 1 joule which I purchased as toys back then at about £15-20 each. All use hop-up and all can just about hit a shed door at 30 meters.
At the end of the day it's a ball spinning on an axis perpendicular to the bore on the horizontal plane to gain additional range, not compatible with spinning concentric to the bore to increase accuracy.
What's the 2000 year old back spin you talk about?
Donald
Did we ever get a link?