If I can clean it from the breech I will, but will still drag the brush back through the business end to get the whole assembly out. In other words that brush goes in both directions, regardless of front or rear entry.
The fact is brass cleaning rods and bronze, or whatever, brushes are softer than steel and the rifling inside. You'd really have to be something special do damage anything but I still take great care when doing so. Then again I'm not a high-power multi-thousands of $ competitor type of guy. If I do compete, it's a CMP match and using what I prefer to shoot: old-ass military rifles that have seen their share of GI's cramming steel cleaning rods down the muzzle.
The whole point is preventing damage to the muzzle where the bullet comes out. If coming in from the muzzle my left index finger and thumb make a great muzzle guide. Free too!