bb weights with WE G39C

[ap27]

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.

[Brian McIlmoyle]

^^^^ Bingo

[Brian McIlmoyle]

Originally Posted by Grizzly0679

Ah, gotcha Brian. I did downgrade; got an m90 spring in my KWA M4A1. Hop up set at its max too. Rifle is a beast!

Really for CQB.. you should be looking at 280 to 300 FPS to be "friendly" and keep the spilled blood to a minimum.. you don't really get any more accurate or better performance by going hotter for close range shooting

I've seen a stock Marui .. shooting 270 take a tooth out at 30 feet..


350 is the MAX not the goal.. it's not like outdoors play were you are engaging targets at max effective range.

[Grizzly0679]

Thx Brian. Any suggestions what I can do to drop the FPS? Is there an m80 spring perhaps? I've been told it's because my rifle is new and that I need to work it in more, but being a city boy that's not always easy to do between games. Only been able to fire 5000bbs so far. And as you guys know, that's not really a lot.

edit: ok so there is such thing as an m80 spring. Thought m90 was the lowest. I guess that's what I need...

Does "working the gun in" do anything? If I fire another 5000bbs will that help at all?

edit: I guess my issue is: I want to be both CQB and mid range field effective. Will the m80 guarantee that?...provided I can shoot straight.