Huben K1 barrel cleaning

Since the K1 Barrel can only be cleaned from the muzzle, I've been looking for cleaning tips and connectors that are made of nylon plastic, or fiberglass. Something other than metal to avoid scratching. So far, I've only been able to find tips and connectors that are made of brass. Even though they are softer metal so, I don't trust them not to damage the crown. Anybody have sources?