The .450 Rigby Rimless Magnum
No one need tell you, dear reader, about the impeccable reputation – well earned, I might add – of the .416 Rigby. For over a century, those .416” slugs have been consistently and reliably dispatching game of all shapes and sizes. However, there are situations where one might find themselves wanting a bigger bullet diameter, or more bullet weight. Paul Roberts, at the time the owner of Rigby Rifles, found himself in just such a predicament in the Zambezi Valley in 1993, facing a bull elephant that didn’t exactly play along to script. Mr. Roberts, according to the tale as I’ve heard it, felt that while the cartridge design of the .416 Rigby was sound (of course), but that a heavier bullet of bigger diameter would be more effective on animals the size of elephant.
He returned to the Rigby workshop, and began the process of necking the .416 Rigby up to hold .458” diameter bullets; once the magic that ballisticians possess was put into full effect, he emerged with the .450 Rigby Rimless Magnum in hand. Maintaining the same case length and 45˚ shoulder angle of its veteran father, the .450 Rigby was set up to drive a 480-grain .458” caliber bullet at just shy of 2,400 fps – a decided velocity increase over the .458 Winchester Magnum and the .450 Nitro Express – putting it right on par with the belted .458 Lott cartridge (the Lott being released just a couple of years prior).
Unlike the belted .45 caliber safari cartridges, the new .450 Rigby used the steep shoulder for headspacing, and the voluminous case allowed for a chamber pressure low enough to give positive extraction, even in the worst heat that the African tropics can throw at you. The great debate that surrounds the .416 Rigby and .416 Remington Magnum can easily be transferred to the .450 Rigby Rimless Magnum vs. .458 Lott; it will boil down to the choice between a belted, higher-pressure cartridge that gives a bit more magazine capacity or a non-belted fatter case that operates at a lower pressure, but at a loss of magazine space. I can see the cases for both cartridges, and understand why each camp would defend their choice.
Both the .458 Lott and .450 Rigby have proven themselves over the last couple of decades, and there are some good rifles available for both cartridges. Norma, however, in their African PH line of ammunition, has given the .450 Rigby Rimless Magnum what I call the “Doctari” treatment. Designed in conjunction with Zimbabwean Veterinarian and noted Professional Hunter Kevin ‘Doctari’ Robertson, Norma has built this line around a pair of Woodleigh bullets – a soft point and a full metal jacket - that are heavier than normal for caliber, at a lesser muzzle velocity, for a greater momentum factor. This formula is just about perfect for the distances at which almost all of the dangerous game is taken, and those round nosed Woodleighs will feed like a dream in a bolt-action repeater. The Norma .450 Rigby ammunition uses a 550-grain bullet, at a muzzle velocity of 2,100 fps, producing 5,387 ft.-lbs. of energy at the muzzle. Even at the lower muzzle velocity, the 550-grain bullet will be only 8.2” low at the 200 yards, when zeroed at 100 yards.
Now while the .450 Rigby will cleanly take plains game and other smaller game animals, it truly shines as a dangerous game cartridge. The .450 Rigby, loaded with those heavyweight Woodleighs, makes a great elephant/buffalo/hippo cartridge, being fully able to stop a charge when the bullets are placed properly. At 550-grains, you’ve got a bullet with a Sectional Density figure of 0.375, and among the experienced Professionals in Africa, any bullet with an S.D. figure above 0.300 is considered a good choice for dangerous game. Compare that figure to the standard 500-grain bullet of that diameter – 0.341 – and you’ll see the appreciable difference, which can be directly correlated to an increase in penetration.
If you’re familiar with the feel of a .416 Rigby rifle, having a magnum receiver and slightly longer bolt, the .450 Rigby rifles won’t feel out of place at all. If you want a true stopping cartridge, in a repeating rifle that doesn’t require the Holland & Holland belted case, the .450 Rigby Rimless Magnum may just be your baby.