Tell them you would be interested in donating money from a charity shoot. Get linked up with these charities. They all have newsletters and your shoot will be advertised for free and many people will arrive to try out the game. When you hold a fun shoot make sure everybody walks away with a prize. A turkey will do.
Losers hate losing.
Shooters care about breaking the targets but they care ever more winning something for breaking targets. Be a winner by creating winners. Don't forget to get your club listed with the ATA . Even if you do not conduct registered shoots ask them to list your gun club as a practice site. Get your club listed on the internet as many Websites are building databases listing gun clubs.