i would stop using BB in your barrel this is putting build up in there form the powder go with a good quality gun oil and before you shot it run two patch down the barrel before you shot it to remove the oil then pop a cap and load it i used BB a longtime a go and it put buildup in may barrel with powder good patch and ball lub and bullet lub in old gun but thats it not inlines oh use the JB to polish the bore good stuff this will help alot