If you can't find a copy of the original, use one from a Browning A-5, same gun. I had a model 11 for many years. It was very reliable. Thereare a couple of friction rings, (one bronze with a steel collar, and one steel ring, beveled on one side and flat on the other)on the magazine tube which must be configured properly for the loads you're using. If it's set up for magnum loads, it may not work for lighter game loads.