So after filling my belly this afternoon I was thumbing through my father-in-laws copy. It may have been my imagination or the post meal coma, but when he is talking about calibers and metric equivalents, I believe all the numbers are off. Is it me or did it read 6.5mm = .256?


....and I've got to admit, I'm asking Santa for a copy. Something about early hunting books has grabbed my attention and I can't quite put my finger on the reason why.

Sounds about right for lands. Grooves at .264. Caliber has been measured both ways. .300 Savage and .308 Win. use the same bullet.

Interesting, never thought of it that way.

A millimeter equals .03937" (or very close to it). Multiply 6.5 x .03937 and the result is .255905, which rounds off to .256". Do the same math and you'll find 7mm is just about .276", which means the .270 Winchester shoots a bullet much closer to 7mm in diameter than any of the so-called 7mm rounds.

The old option of naming cartridges by either their bore or groove diameter isn't limited to non-metric rounds.

I haven't read the book in years, but my guess would be a typo referencing the .256 Newton, which I believe would have been a 6.5 or very close. That was part of the old nomenclature from the 19th century, where they also called the 7x57 the .275 Rigby.

forepaw

It isn't a typo.

Yep, just checked my old copy and it is all there, with good clear explanations.

forepaw