I have a Bartlein 6br, it's cut for a origin, put it on a solus for my nephews Christmas present this year. Had 400rd on it when purchased according to seller. It has some barrel worms. I used some thoroughclean on a iosso blue brush, and got rid some, reduced size of others. But OMFG I USED AND ABRASIVE! It shoots great! But it's a 6br, you gotta try to make them shoot bad.