My first question is why are you feeding in a bucket rather than feeding in your bp's normal enclosure? To me, feeding in a separate enclosure has no benefit, and only stresses your bp out, which could lead to illness, feeding refusals, or regurgitation.

Secondly, how long are you letting your bp try to swallow the meal on its own before stepping in and grabbing the mouse to turn it around? I've often thought my little girl was "special" because it seemed that she tried to swallow every meal bum first. She would work at it for 5-10 minutes, trying to manipulate her jaws around the back legs and tail, then she would let go, sniff around and eventually find the head.

I'm almost certain that if you feed in the snake's enclosure, let the snake strike and constrict, then allow the snake to swallow the prey without interference, he/she will almost certainly find the head for him/herself just fine. Even if he/she doesn't find the head and swallows the prey bum first, it shouldn't harm the snake as long as the prey is of appropriate size. In fact, I actually have a pic on my cell phone of my snake eating bum first, with nothing but the head sticking out of her mouth...