Any petition to repeal the Hughes amendment can accomplish something positive only if, in the current political climate, a movement for repeal even has any "legs."
Consider, how many Congress Critters would not believe that their chances of re-election would be hurt by their opponents pointing out that they voted to make machine guns more available to private citizens? Sure, there might be a bunch of us who wouldn't care (and even might think it's a good thing). But there are probably too many voters who would think differently.
To put it another way, how many signatures do you think you'd need on the petition to convince enough Congress Critters that it would be worth it to put their careers on the line to vote for repeal of the Hughes Amendment? Do you really think you could get that many?
Bottom line, I'm afraid that politically this is probably a non-starter.
"It is long been a principle of ours that one is no more armed because he has possession of a firearm than he is a musician because he owns a piano. There is no point in having a gun if you are not capable of using it skillfully." -- Jeff Cooper