I worked in an amusement park for a summer. At the time, it was called Riverside. It is now Six Flags over New England.
I used to work that game fairly often. The guns aren't rigged, and the sights aren't really off. However, the bb's are lead and are reused ad-infinitum, and the bores are smooth, so they aren't exactly the most accurate things.
The trick is to shoot the points and then cut out the middle.
By the end of the summer, I could do it maybe 1/3 of the time.
The guns we had held 103 bb's. We had a device that we would stack the feed tubes into. Then we would put another piece on top that was basically a bucket that had holes that lined up with the tubes. We'd scoop the bb's out of the trap and into the bucket to fill the tubes. The problem was that our feed tubes would hold 104 to 105 bb's. This meant that as we loaded the guns, we would bump the top bb out of the tube, so the gun wouldn't jam. Of course this led to no end of problems with people who actually saw us do it, and would make a stink. By the end of the summer, I had a plan. I'd tell them they could have that bb back, but if the gun jammed they lost, and they wouldn't get a second shot at it. If they accepted the feed tube the way I wanted it, and the gun jammed, they'd get a second feed tube to shoot at the same target.
I never ever lost this bet.
By the end of the summer, I could tell who would challenge me on it, who would insist on the extra BB, and who wouldn't. I could also usually tell who was going to win the game in just a few tries, by what they did with the first few shots.
On a night with 8 or 9 thousand people in the park, we would generally give out 2 or 3 prizes. For that park, that wasn't busy, but not dead either.
It was a great game to work at except for Friday and Saturday, when the park would be full of drunks from the concert or the race. Generally on those nights, one of the supervisors and a security guy would basically be stuck in the booth to handle the complaints and people that wanted to teach "that 17 year old punk a lesson!"
My understanding is that the game was one of the top 3 money makers in the games department, beat out only by the ring toss and the dime toss. Part of the reason is that those giant animals were only worth about $3, circa 1994. All of the summer employees were paid less than minimum wage, because we were seasonal help, and for some reason, we fell under the rules for migrant agricultural workers. I was always amazed at how much people would put into those stupid games, and it was almost always folks that probably couldn't afford it. Working the ring toss, I watched a woman spend about $160 before she finally gave up. I watched another guy trying to win (and I remember this very clearly) a large Tweety Bird for his gf. It was probably 4 feet tall. IIRC he spent $120 on the dime toss before he finally won. The tweety bird was the most expensive prize in the park. It cost the park about $7. The dime toss was located just outside the race track entrance. On a busy Saturday night, the game would have two employees for 14 hours, give out 4 prizes, and take in over $2k.
That whole job was a great learning experience for me. I was shocked to learn that most of my coworkers were stealing from the park hand over fist. The length to which customers would go to cheat was amazing. For a kid that would turn a dollar found on the ground into the lost and found, it was a real eye opener.