Although the Long Island Republicans backed the SAFE Act I think the Senate is of more immediate interest than the Governor's race. Astorino is a longshot, yes Democrats vote less in off year elections and yeah maybe Democrats will stay home because they never even heard of Astorino while motivated Republicans upstate will turn out in hordes-but the GOP has a much better shot at keeping the Senate than getting Astorino in.
If the Senate falls to the Democrats it will be gunpocalypse. Both houses and probably the Governor's office will be controlled by Democrats. We will see microstamping passed and many pistol manufacturers will just stop selling in NY. We may see a new SAFE Act that will restrict registered assault weapon possession to the home and the range, no hunting or just having one in your car, we may see restrictions on owning more than two magazines for a firearm (that has been proposed before), requirements for insurance that will be super expensive or maybe unobtainable, requirements that firearms have to be always locked up in a safe at your home and on and on.