I just installed a Choate 7-shot magazine extension on my Win. 1200 and have a jamming issue. The threads on the inside of the extension collar are about twice the length of the threads on the mag tube...leaving 1/2" - 3/4" of the extension's threads exposed in the tube once assembled.

This is causing the follower to catch on the threads and bind. The first two shells feed fine, but once the follower gets to the extension/tube junction it stops. I've tried using the Choate follower included with the extension, the original Winchester follower, and an S&J Hardware follower..same issue with all.

Has anyone else experienced this issue with a Choate (or other brand) extension? Or found a mag extension that feeds 100%? I haven't had this issue with magazine extensions on my other shotguns.

My first inclination is to caveman it and either Dremel the unused threads smooth (although I'm concerned the follower would just then catch on the front edge of the mag tube where it meets the extenstion), or fill in the unused threads with epoxy/JB Weld.

Thanks!