Cartridges of the World say that the 256 Gibbs Magnum is essentially the same case and capacities as the 6.5X55mmSE.

Is this another case of the 7X57mm Mauser and the 275 Rgby? Are they really the same just one was loaded asa proprietary catridge by Gibbs?

I figured this was the best location to ask?

333:

No, the 256 Gibbs is not a clone of the 6.5x55. The following measurements were taken from a Kynoch .256 Gibbs Magnum and a norma 6.5x55.

.256 Gibbs: case length, 2.158"; length to shoulder, ~1.75"; neck length, 0.225"; head diameter, .471"; shoulder diameter, 0.423".

6.5x55: case length, 2.157"; length to shoulder, ~1.71"; neck length, 0.296"; head diameter, .476"; shoulder diameter, 0.435".

The shoulder angle on the Gibbs is also much less than that of the Swede (it looks to be about half as much). The headspace of the Gibbs should make it too long for a Swede chamber, and the Swede should theoretically be too fat for the Gibbs chamber. However, if it could be coaxed into the Gibbs chamber it would have excess headspace. These two cartridges appear to have about as much in common with one another as they do with the 6.5x57 Mauser and 6.5x58 Portuguese, i.e., similar case capacity but somewhat different ideas as to optimum case shape.

Cheers, Al

I was wonder since the book made them sound as the 7mm Mauser to the 275 Rigby. Just not the case! Hahaha

333, as Al's answer demonstrates, they are comparable designs & very similar, but not different names for the same round.

Iconoclast--

Thanks for your help. I see your not just on the IAA.

I move around a bit, 333.

quote:

Originally posted by Iconoclast:
I move around a bit, 333.

Harder to hit a moving target, eh?

Ray