Try some pillowticking you can buy it at Walmart. It will set you back about a buck fifty for half a yard which if it works will last a good long time. If the .490 loads regular not real easy with the patch you are using just try it with the balls you have, I think the pillow ticking is .015 a bit thinner. If it is already loading real easy you may need to try .495 ball with that material.

The reason I suggest trying this stuff is it is very rugged the only time I ever blew it out was with 90g charges of T7 in a real rough bore.