Ah I understand. Using heavier BBs in an AEG would drop the velocity to keep the same muzzle energy (as determined by the cylinder volume). If an AEG and GBBR are both firing at 400fps with 0.2s, using heavier BBs will drop the fps of the GBBR but not by the same amount as the AEG (since its gas pressure here that matters, not cylinder volume), hence the higher muzzle energy.
Originally Posted by Brian McIlmoyle
yes you are... they show an increase in muzzle energy , which is a measure of the kinetic energy of the projectile.
muzzle energy in AEGs is fixed by the volume of air in the cylinder. so it drops as the projectile mass increases..
The force that a bb hits with is pretty much fixed with a AEG regardless of the weight of the projectile.
Heavier projectille gives you more stable flight over a longer distance, and greater penetration through leaf cover.
With gas guns .. the volume of propellant is not fixed.. with a heavier projectile, the time that the gas valves remain open and delivering gas is stretched out as it takes longer to accelerate the bb out of the barrel with a heavier mass..
so the heavier the bb the more gas is delivered to propel it.. the more Muzzle energy it will have upon leaving the barrel.