Читать книгу Gun Digest 2011 онлайн

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The important difference between the two cases is the shoulder angle. This is very important because for rimless cartridges, as both of these are, the headspace length is determined by the distance between a point on the shoulder and the base of the cartridge. When the angle of the shoulder is changed, the length of the headspace is also changed. If you put a cartridge with a shorter headspace length into a longer barrel chamber, you instantly create a condition known as “excessive headspace.” This may result in a case rupture and can cause serious damage to the rifle and shooter.

The Jeffery has a longer shoulder angle of roughly 12.5 degrees. The Schuler utilizes a shorter, steeper angle of a bit over 19.5 degrees. The consequence of putting a .500 Jeffery cartridge in a .500 Schuler chamber is that you create excessive headspace. And, conversely, putting a .500 Schuler cartridge in a .500 Jeffery barrel makes it difficult or impossible to close the bolt.

C.I.P. (Commission Internationale Permanente pour l’Epreuve des Armes à Feu Portatives, the European equivalent to SAAMI) standardized the dimensions for the “12.7x70mm (.500 Schuler),” its official name, in 1998. The “500 Jeffery” received C.I.P. approval the following year. Both were slightly revised in 2002. A quick look at the dimensions shows that while similar, they are different in nearly every dimension. With C.I.P. standardization of the two cartridges coming ten years ago you would think, “What’s the problem?”