I don't use them anymore, but there's nothing wrong with boresnakes for getting out the majority of powder fouling in the field. They do little to nothing with copper buildup, however.
Keep in mind, however, that the "rope" of the boresnake accumulates grit and debris, which embeds on the cleaning surface of the rope. Keeping the snakes clean is important. I used to put mine in a laundry bag and toss them in the washing machine on a regular basis.
Mike