Ok JG likes to exagerate just a little tad of a bit , this gun may shoot this with .12 grams bbs , but with .25s , ( which is the lowest grade that I reccommend for a bb ) , it will probally shoot somewhere around 420 to 380 , but upgrades are cheap and easy for this gun .
I have a Bar-10. Out of the box with .2 it is over 400 and i can fire 150 ft accuratly out of the box. I put a df 6.02 barrel in it and now it is over 300 ft accurcy
With .30 gram BBs it should go around 380-400 fps(i think) it will also hurt a lot more when you get because its a denser bullet. You will also MUCH more accuracy. The wind will also have a harder time changing the course of the BB because it is heavier.
Ok this is what I have to say on weight yes a great gun with a bad bb you wont even hit a tree at 2 ft but bad gun good bbs wont do anything either. I say use bbs for the right time if you dont have wind (indors) .2 are ok but I would still use .25 if it is windy you will have to go with a heaver high quality bbs
Ok this forum has gotten completely off topic , please revert back to the topic or I will be forced to close this forum , sorry I know that I had some part in drawing the posts off course .