Like any good wildcatter possessed with the common sense of a fern, my first impression upon seeing the new .375 Ruger was: “Gee, what can I use this unique new case for wildcatting-wise?” Never mind the cartridge’s considerable merits as a .375; all I could think about was what kind of cartridge I could come up with by necking it up or down.

I think by now everyone knows that this .375 was developed for Ruger by Hornady and as such is among the latest batch of nearly a dozen new cartridges--both rimfire and centerfire--introduced in recent years by this innovative Nebraska-based reloading equipment and ammunition manufacturer.

The .375 Ruger is new as a commercial cartridge but not as a proprietary one. John Lazzeroni has that distinction, as he came out with the same basic case back in the early 1990s, but it was short lived. You see, the Ruger’s case head is of the same diameter (.532 inch) as the belted H&H case with which we’re all familiar. The difference is that, where the belt on the H&H case steps down .020 inch to form the headspacing surface, the Ruger case does not; it continues forward at that .532-inch diameter, and as such the entire body of the case is about .020 inch larger in diameter from head to shoulder.

That of course means the volume of the case--its powder capacity--is greater, all other things equal. So even though it is about a half-inch shorter than the belted H&H case, it actually has greater volume--though only marginally. The average capacity of the three different brands of .375 H&H Magnum cases I weighed came to 97.5 grains of water when filled to the case mouth, whereas the Ruger case held 100. Because of this, the .375 Ruger not only matches but exceeds the ballistics of the vaunted H&H round, and it does it in a standard--rather than magnum-length--action, which is its raison d’etre.

Obviously, that same advantage can apply to other calibers, and most notable in my mind was .416. And a similar comparison to the one just mentioned can be made using the .416 Remington Magnum, which is based on the full-length H&H hull, though “improved” in wildcatter jargon, by sporting less body taper, a sharper shoulder and a shorter neck.

The resultant case holds 105 grains of water, so the difference between the nominal ballistics of the .416 Remington and a .416 based on the Ruger case should be very similar. That rationale prompted me to go ahead with what, for lack of a better designation, is the .416 JRS.

I ran the idea past my friend George Sandmann, the guy who runs Empire Rifles. George volunteered to put together a rifle because it not only made sense to him but also because the majority of guns he builds for clients (all his guns are made to order) are in dangerous game calibers, so he knew that when I was through with it, he wouldn’t be stuck with an oddball he couldn’t sell.

By that time, the dimensional specs for the .375 Ruger had been registered with SAAMI, so what little changes had to be extrapolated from those specs to arrive at the reamer and chamber dimensions for a .416 version were easily computed.

Ditto for the reloading aspect. A call to Dick Bebee of Redding Reloading, a guy who’s always interested in projects such as this, and arrangements were made for reloading dies.