With the greatest respect, I really don't feel there's much point in a petition at this stage. When this was first proposed there was a petition that achieved many thousands of signatures and it has generally been ignored. There has been an official panel of people in Scotland steering this, which has included BASC and the police as well as the politicos. The SNP was elected on a manifesto that included taking action against airgunners and back garden plinking in urban areas, so , quite simply, they aren't going to back down.
I believe the most effective and worthwhile thing airgunners can now do is to respond to the formal consultation in a constructive manner. If you have a look at it you'll find that it is laughably poorly framed in several areas - loopholes you could shoot something larger than a .177 through.
One thing that shooters might consider saying could be along the lines that in return for giving up a "freedom" (to own an airgun without control) the ScotGov should introduce local authority managed shooting grounds / ranges, where anyone owning or wanting to own air weapons would undergo a short course on safety and responsible use; these ranges would also provide a safe place for plinkers to shoot, or they could subsidise private members clubs to undertake the same function and provide the same service. That way we might truly encourage safe shooting and bring extra people into the fold rather than merely antagonise shooters.
You can get more information and link to the consultation document here: