BB's

OK, besides the weight what is the difference? How do heavier one preform apposed lighter? Decrease FPS? Shorter distance? More accurate?

Heavy BB= slower but more accurate because the flight path isn't as influenced by the wind/environment/ etc/
Lighter BB= Pretty much the complete opposite of a heavier gram BB

So what is the best weight for an AEG, to get the most accurate shot without losing to much range

What FPS are your guns?

Its all user preference. I find that my vfc shoots well with .28 bbs. It chronos at about 385 with .20s, so the .28s get it down to about the 365 area. But get a small amount of each kind of bb, like enough to fill up a half a mag or so, and before the morning game start test out which weight works best for your gun or your preferences.

There is no best weight for BB's each AEG will shoot differently with different Weight bb's

Think of it like this, if I throw a wiffle ball at you as hard as I can it will travel super fast for the first little bit but it will get slower towards the end of its travel.

if i throw a hardball at you, it will travel slower but it will retain its speed over a greater distance.

0-400 FPS I am a firm believer that .25 and .28 are the best weight. Each AEG will be different. And just like meatshower said heavier bb's will be effected from the wind less than light weight bb's

.20's in my opinion are only good for CQB pistol games where the engagement distances are no further than 80FT. in this type of scenario a faster slightly less accurate bb can have the edge over a head bobber.

Barrel length can make a difference too. .28 in a long barrel gun shooting 400 fps will give you better distance than you might think, and better accuracy too. With .25, you will lose the accuracy but gain a bit of distance, maybe. But who knows where your bb will go at that point.