Been thinking about a big bore revolver and looking at Ruger's website I see they offer at Blackhawk .357 in a convertible model with a 9mm cylinder. I already stock 9mm and it is cheaper to shoot than either .357/.38 Special. Would this be worth the $70 up-charge or is the 9mm cylinder going to be inaccurate and not worth the cost savings on ammo? The other revolver on my short list is the GP100. Don't think I would go up to a S&W but on a good sale a 686 would be a possibility. Not interested in Taurus-too many quality issues. Any other options I'm overlooking in the Blackhawk price range?