The a400 has pretty thin chokes so I'd like to steer clear of any chokes that have had issues but it sounds like Indian Creek has changed the steel for the better. Not sure if that is the issue you are talking about. They've been talked about as a good choke for awhile so must be doing something right.
Sumtoy sounds like a good option to look into or maybe pure gold.
Just got the a400 today and took it out and shot a couple hundred clays. Think I'm going to really like it after shooting pumps but chokes are a lot harder to find in stores. If it was an 870 I'd just go buy a jellyhead and call it good.
I'm doing good, had an awesome fall and did get a lot of good pheasant and waterfowl hunting. Ready for spring weather,spring hunting, and spring fishing.
Thanks