I would contact Briley and ask them.How safe would it be to use steel shot in a Belgian made 12 gauge 3" barrel with a Briley S-1. 705 steel choke. Main usage will be waterfowl.
This is relevant, I think - so way back in the day when "non-toxic" shot became a requirement for waterfowl in Canada, I looked into the issue - and I may have got it muddled up today. But, I think "choke" is a restriction - a reduction in diameter - is not an absolute fixed dimension - and many shotgun barrel makers decide they will make their bores to their own unique diameter - not all are the same - for sure, not one brand maker to another - have to measure to know what the bore size actually is, in your barrel. Then, a "choke" is a reduction from that diameter. So, for example, you can have a nominal 12 gauge bore that measures 0.730" or 0.725" or some other diameter - the same diameter restriction (the same item) screwed into either barrel will give different constrictions - should result in different patterns, or at least "level of choking". So, a "choke device" that created 0.005" constriction from the bore diameter, could be several different sizes, since the bores tend to all be different sizes. Actual measuring and patterning and counting shot pellet holes on target is required to know - versus what the "made-in-China" package says it is. I believe that I read that choke "count" or choke "name" actually refers to the percentage of shot that lands in a 30" diameter circle at 40 yards - for example, I think it is 70% of the shot fired is called "full choke" - is NOT a dimension that you can measure and therefore "know" what it is.Belgian A-5's have nominal bores of .725" compared to NA standard .730" which makes for crappy performance when using steel shot.
Many nice old Belgian A-5's have suffered barrel damage from steel shot use.