Cook the shrimp according to the package instructions.
Meanwhile, add the butter, garlic and 1/2 teaspoon salt to a small pot over low heat. Cook, stirring occasionally, until the garlic softens and toasts slightly, about 10 minutes.
Finely chop 1/3 cup of the pickles and whisk together with the sour cream, mayonnaise, hot sauce, 1/2 teaspoon salt and several grinds black pepper in a small bowl.
Slice the bread in half lengthwise, leaving one of the long sides connected, and open the loaf like a book. Hollow out the middle of the bread about 1/4 inch deep, saving the crumbs for another use. Spread the mayonnaise mixture over the bread, layer on the lettuce, tomato and remaining 2/3 cup pickle chips and top with the cooked shrimp. Stir the parsley into the butter mixture and drizzle over the sandwich. Top with a couple dashes hot sauce. Close the sandwich and cut into 4 portions. Serve with potato chips on the side.