OLYMPIA - Supporters of a ballot measure to allow the state to open as many as 40 charter schools over the next five years turned in petititions with some 350,000 signatures today. Initiative 1240 needs about 242,000 signatures to qualify for the November election and with more than 100,000 extra, it is all but assured of making the ballot. Previous ballot measures on charter schools have failed at the ballot box and in the Legislature. But Rep. Eric Pettigrew, D-Seattle, said this is a more modest proposal with stronger controls. Supporters refused today to say who they hired to gather enough signatures in less than a month to have a strong chance to make the ballot.