I have never heard it put that way (clean in the direction the bullet goes). The main reasons to clean from chamber to muzzle is:
1- prevent damage to the crown
2- prevent gunk from being transferred from the barrel to the inside of the receiver.
hey sam, i suppose you mean as in a ruger 10-22? yep, all mine are drilled. all i used was a 1/4 inch drill bit to do it, i just eye balled it and got real close enough to use a cleaning rod. then they come out with the BORE SNAKE, MUCH SIMPLIER, AND CHEAPER IN THE LONG RUN!!!!! i take the brushes out before use, as more bores are ruined with brushes than need be, imho. just my .02. good shootin!!!