[mamelukesabre]

Well, my book says american 30 calibers are either .308”, .3085”, or .309”. The british 303 is .312”

And they are not interchangeable.

[Copernicus]

Well, my book says american 30 calibers are either .308”, .3085”, or .309”. The british 303 is .312”

I will cheerfully read your book if you will supply the title and author.

Best regards,