>>8737942
Some good news and bad news.

Bad news is that this is probably a private commission. I have no clue who the artist is or if there is even more than just that page.

The good news is that I know the image is a parody of Mahou Shoujo Western Girls/魔法少女ウェスタンガールズ.
Pic related by Suukaizou drew the same scenario which is about as close as it gets.

Good luck to anyone else who wants to dig further into this.