African Outfitter Back Issues: CONTENTS - June / July 2006 - (Vol 1/4)
Favourite rifles and terminal performance
In this edition we interview professional hunter Ivor van Wyk regarding his beloved .500 Jeffrey custom-built rifle.
Ivor is an avid believer in the .500 Jeffrey when dealing with dangerous game. This rifle was initially bought from Classic Arms in Witbank. In the beginning this rifle was plagued with many problems.
Chambering proved difficult with most bullets even in a properly full-length resized case. This problem was eventually solved by the people from Truvelo Armoury and a brand-new reamer. The rifle itself is based on a Brno ZKK602 action without the peep sight. The barrel is 24 inches long and was originally also supplied by Truvelo Armoury. In its assembled form this rifle weighs 10½ pounds or 4.8 kg. Like most custom-built .500 Jeffrey rifles, this rifle also needed some fine tuning for the proper feeding of cartridges from the magazine and the ejection of fired cases.
With the basic requirements pertaining to a large-bore calibre rifle sorted out, Ivor has put in a lot of exercise with this rifle. This implies that he and countless .500 Jeffrey owners in southern Africa had to resort to the reloading of this cartridge, given the prohibitively expensive retail prices of available loaded cartridges.
This is especially true with regard to the ammunition from Wolfgang Romey of Germany and Kynoch from Kynamco, England. Cases were therefore procured from Betram, Australia, while Ivor has opted for the locally produced Rhino bullet in .510 diameter. Federal primers designated as being .215 Magnum have given consistent ignition with this large case.
Initial reloading trials centred around the usage of Somchem's S365, more or less the equivalent of IMR4350. Velocities of up to 2 250 feet per second were obtained in Ivor's rifle with no indications of extreme pressure. The most preferred load with S365 was 109 grains with a 540 grain Rhino soft.
What is quite revealing here is that hunting associate and friend, Jaco Marais, has used up to 120 grains of S365 behind a Rhino 540 grain soft to achieve a muzzle velocity of 2 220 feet per second. His rifle is built on a pre-64 Winchester action with a McGowan-barrel. Before the chamber was cut with a "roomier" reamer, Ivor's rifle started to show signs of extreme pressure around 111 grains of S365 and the 540 Rhino bullet. What is of critical importance, is the fact that Ivor's rifle now has a free-bore factor of around 2.5 millimetres, even when loaded with the longer 570 grain bullets and the especially long Barnes Super Solid. This bullet is 36.1 mm from tip to base.
One must remember that any rifle has its own ballistic "personality" and therefore even two barrels made from the same bar of steel, the same set of tools and nearly the same tolerances, may produce different pressures and velocities, even when used with the same components. With the .500 Jeffrey the free-bore factor as well as chamber dimensions is of critical importance.
In the end Somchem's S355 (± IMR4320) gave more consistent velocities with all the usable bullet weights in the .500 Jeffrey. Somchem's S341, a ball propellant, was discarded rather early in the reloading trials simply because of pressure spikes in extreme hot weather conditions. Using a RCBS die set with a 20 degree shoulder angle, Ivor's .500 Jeffrey delivers the following performance with certain components:
These loads were chronographed with an Alpha Chrony chronograph placed 6 metres before the muzzle of Ivor's rifle.
Ivor has used this rifle on buffalo on more than one occasion. During April this year, a Canadian client wounded a buffalo with two marginal shots from a .375. In the follow-up Ivor's partner and professional hunter, Pieter Diedericks, had to fire two shots through some dense brush with a .416 Rigby, which slowed the buffalo down. The buffalo then turned and put in a very determined charge. Ivor managed to put the buffalo down with his .500 Jeffrey at a distance of about 15 metres with a spine shot where the neck joins the body/shoulders. The recovered Rhino 570 grain soft retained 568 grains of original weight. From Ivor's experience with this buffalo, one gets the definite impression that he simply adores his .500 Jeffrey and above all really knows how to handle this impressive cartridge.
(No responsibility, either expressed or implied, is assumed for the use of the reloading data published in this article. - Ed.)
Copyright © - 2013 African Outfitter. All Rights Reserved.