As we've seen with Space Ace, those pop guns get everywhere in space. They pop up on auctions constantly.
The 80's was awash with target sets like this Space Robot set with a cork gun.
You could get it in different colours and with small plastic red pellets too.
Not sure if the rather snazzy card art is lifted from an arcade game. You?
Here's a more infantile illustration on more or less the same set too.
For larger ammo you could move up to ping pong balls and a particularly chunky see-through pistol.
Here's one boxed called Space Battle, which has some really great box art, some clearly 'inspired' by Star Wars but some not. I love the circular space station and the big ship up top; where are they from?
Here's another boxed Space battle target game. You can see the toothed rings on the pistols, which recall those on the Force toy gun we saw on MC last week.
This particular specimen is from the V&A collection no less, where the Star Wars riffing hasn't gone unnoticed!