I've managed to find a rifle-sighted smoothbore IC barrel for a Remington 870 Express. It's got the hole for the ball-bearing detent in the retaining ring, but of course has no ball in it. Is it possible to insert a ball bearing into this socket, so that the barrel can be used with the magazine cap of a standard 870 Wingmaster? If so, how does one insert the ball - in other words, is it a job I can do at home, or is a gunsmith required?