Are there factory 20 gauge bunker trap loads?

If you are asking if there are 24 gram 20 gauge cartridges - answer is yes.
24 gram is very close to 7/8 ounce, the normal 20 gauge Target load in N. America.

Yeah, I know the shot weight is close. But...7/8 still not legal for bunker and the shells are a lot slower that 12 gauge bunker loads. So I am asking are there 20 gauge shells made and marketed for bunker?

The short answer is "no".
Bunker is shot competitively with a 12 ga worldwide.

Thanks mudpack. That is the conclusion I came to also. Tough game, at least for me.

And that is what makes it so much fun!

As for 20 gauge bunker loads, you could reload some to around 1,250 fps but as said before, there is nothing from the factories. BTW, there is no need to have the shot leave muzzle at 1,300+ fps. If you don't believe me, try shooting some bunker for practice with a 1,145 or 1,200 fps load and watch the targets break decisively!

For playing the game the 20 gauge reloads would be fine but all competition requires a 24 gram load. That could also be done with a minor change in a shot bushing, although many throw a bit light anyway. If you check you might find you already have a bushing that drops 24 grams of 7 1/2 size shot.

Have fun-it is a wonderful shotgun game!

There are 20 gauge 24 gram loads at 1300 fps. A quick Internet searchwill show them.
Whether they are readily available is another question.

Crown Grade is correct but interesting that down under the standard trench load is 24gr at 1350fps.

Winchester has 20ga AA Supersport load that’s 1300. Should work.