Paul, thanks for the proof confirmation, I was just stating what I thought to be true, but did not know.
Your Mod for a rimfire sounds good, but does not need to stand the higher pressures of 243/308 etc. Even so there are an awful lot of people who do not have the skill or facilities to make it like you did. There will always be skilled engineers who can make a better mousetrap, but the factory produced Mod will still be the only option for most.