You don't need a 'Trap' gun to shoot trap any more than you need a 'Skeet' gun to shoot skeetor a 'Sporting Clays' gun to shoot that course.
To get yourself started, have fun and even shoot 24 or 25/25,,most any field gun will do the trick.
All you need to do is be able to shoot.
A vent rib, or a particularly fitted stock, a special front bead,,none will make you a good shooter.
Any of those make help a good shooter be a better one on any particular course. Gaining one more target over a hundred or 200 target course makes a big difference when you are in that level of the game.
When $$ is at stake,,it means everything.
But for the average weekend shooter , most any plain field gun will do.
Pick a gun that you like, feel comfortable with.
You won't break the targets if you're not on them,,no matter what the gun and how expensive it is nor the brand name.
You must still learn target lead to the left and right even with a Trap Rib which places the shot pattern high for the rising Trap targets.
Each station of the 5 presents it's own different target flight picture.
The gun isn't going to do it for you.
Some days it will seem as so and everything you point at breaks into powder.
Got this game down!
Then the next time you may leave the Trap Field thinking you'd have a hard time hitting them placed on the ground in front of you.
Start with something friendly to you, handy, you feel comfortable with.
Pump, semiauto, O/U, whatever. Don't be Brand conscious. You'll get looks from othr shooters no matter what you bring to the line.
Don't let gadgets clutter your shooting. Gloves, special glasses w/ varying colored lenses, interchangeable front sight beads and such other sighting gadgets,
Choke tubes are common (now), but don't fret over changing them if you start missing a few targets thinking it's the problem.
Before choke tubes were around,,....
If you get stuck with a group that isn't the most friendly to shoot with,,and it happens,,,find another group. You only need 4 plus yourself for a Trap squad.
Some shooters can't seem to shoot with a newer shooter to the sport and that can place a lot of pressure on that new guy.
Above all,,you are there to have some fun.
The ATA stuff comes much later.....