is 260 fps ( 80 m/s ) enought for a AEG rifle ? i mean like on a Berget event?

If you have an usual assault weapon on berget, and you have one typical battery (8,4V ore something in that way) do you need more then 1 battery for berget or is it enougt whit 1 ?

I though't it would be nice with a question topic here , ask the questions and hopefully they will be answered by the members of this forum