It looks like you already received your answer to your inquiry here
http://oldgobbler.com/Forum/index.php/topic,69829.msg680972.html#newI've shot that choke in my 835s, my 935 and my SSi-ONE without incident, with Hevi-13, WLB and other turkey loads. It has delivered excellent patterns without 2" or larger gaps.
All manufacturers of barrels and chokes have tolerances of +/- some number. If a choke happens to be on the high side and the counterbore or threads of the barrel on the tight side, you can have a problem with fit and that will become worse many times after it's fired.
The main reason a choke swells is that shot can bridge and that swelling usually occurs at the weakest point in a choke tube, near or in the threads. Than can make a choke very hard to remove and impossible to reinstall. It's more common with large shot but can happen with any size shot.
You can guard against some problems by cleaning the counterbore (a forgotten area for many shooters), cleaning the threads in the counterbore and on the choke tube and checking often to make sure a choke is tight against the interior shoulder of the counterbore, which is especially important.
Thanks,
Clark