One of my Briley Helix Hunter chokes split after less than two years of shooting -- and it haven't seen steel shot yet, just target loads, mostly, and some copper plated lead pheasant loads.
The good thing is that my barrel was not damaged (even though it would've been quite possible). Also a good thing is that Briley offered to replace the choke for free. (I would've been out of luck if the barrel was damaged, because Briley takes no responsibility for that...)
The bad thing is that I had to send them the damaged choke -- and International shipping was half the price of the choke.
Another bad thing is that Briley ships by USPS, which - to cut the long story short - means that the parcel will be stuck in Customs for months (previous parcels from Briley spent three, respectively two months in Customs). Two of the chokes came badly rusted after spending two months in God know what damp warehouse of CBS...
(On a side note, I still haven't figured out how is it possible to get such bad rust on some stainless steel chokes, coated with something that's supposed to be extremely tough...)