Gun Digest 2011. Dan ShidelerЧитать онлайн книгу.
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?”
The problem is that with the longtime misrepresentation, many people have the mistaken idea that they are the same cartridge! This translates into rifles being marked .500 Jeffery that have the Schuler chamber. Chamber reamers have been marked .500 Jeffery/Schuler. Brass has been headstamped .500 Jeffery that won’t fit into the chamber of a .500 Jeffery rifle. This can be very frustrating, costly, and potentially dangerous.
If you have a .500 Jeffery rifle and are experiencing difficulty opening the bolt after firing and/or the primers are flattened, STOP. Do not continue to fire your rifle. These are signs of excessive pressure. Take your rifle and ammo to a knowledgeable gunsmith and have it thoroughly inspected. You are probably firing .500 Jeffery ammo in a .500 Schuler chamber.
David Little of Kynamco Ltd., makers of Kynoch ammo, pushed for and got the CIP standardization of the .500 Jeffery cartridge. He provided the best explanation as to the design of the .500 Jeffery and backed it up with physical evidence. To paraphrase:
While both gunmakers built rifles using Mauser actions, Schuler’s design incorporated a straight stack magazine to accommodate their cartridge while Jeffery stayed with the Mauser double stack design. Also, the German bullets of the time came apart and failed to penetrate deeply on thick skinned game. W. J. Jeffery used a longer shoulder angle for feeding, a thicker jacketed bullet for better penetration, and cordite powder to create the .500 Jeffery. Jeffery was not an ammunition manufacturer and probably had Kynoch do all or most of this on his behalf. It is likely they got Schuler “basic brass” cases from the German manufacturer and then formed and loaded it to Jeffery’s specifications. It seems obvious that Schuler came up with his cartridge first. It is equally obvious that Jeffery did not “steal” Schuler’s cartridge and put his name on it, as some have said.
The .500 Jeffery is an excellent cartridge for dangerous game. It is not a 12.7x70 mm (.500 Schuler). Treating them as the same can be dangerous to humans and fine rifles.
.500 Jeffrey (left) and .12.7X70mm/.500 Schuler (right). Note the difference in shoulder angle.
Big bores are notorious for not being accurate. Two-inch groups at 100 yards are often considered adequate, but when author shot this three-shot group using 570-grain Barnes Banded Solids he was elated.
To add a little more flare I decided to have some metal engraving as well. Michael Gouse of Gouse Freelance Firearms Engraving was contacted and a decision was made to have him do a modest amount of scroll engraving, and seeing how a couple of Cape buffalo brought me to this point, he would appropriately include an engraved Cape buffalo head on the floor plate.
In cases like the .500, finding reloading data can sometimes be a problem, but I was fortunate to find data on a couple of websites as well as in a reloading manual put out by A-Square. This provided a good point to start from and eventually I compiled my own data. (See table below.)
.500 Jeffery Rimless Reloading Data
Note: All of these loads shot to the same point the in the author’s test Rifle at 100 yards. No signs of excessive pressure were noted and all rounds functioned flawlessly. Starting point references: 1) http://www.accuratereloading.com/500jef.html;A-Square Reloading Manual. Warning: Even though these loads were felt to be safe in the author’s current Rifle, ALWAYS start 5-10% below listed charge and work yourself up to a safe maximum level in your firearm. The author or this publication takes no responsibility for any result using these loads.
Quite astonishing to me was the fact that virtually all of the tested loads impacted at the same point on paper at 100 yards; even the Barnes Banded Solids cut paper at the same point as the Triple Shock bullets. This is an important consideration when contemplating going after dangerous game. The rifle consistently held all of its rounds within 1-1/2 inches and on several occasions they cut a single 3-shot ragged hole. This is considered exceptional by any big bore standard. Extreme accuracy and beauty, all in one firearm – what more could a shooter ask for?
CONTACTS
Coffin Gunsmithing, LLC (Gunsmithing) 375 Sweathouse Creek Rd. Victor, Montana 59875 E-Mail: [email protected]
Pam Wheeler (Checkering) P.O. Box 827 Stevensville, Montana 59870 Telephone: (406) 381-1484
Gouse Freelance Firearms Engraving (Engraving) 708 Adirondac Hamilton, Montana 59840 Telephone: (406) 363-0254 E-mail: [email protected] Web: http://www.mtart.com
Pacific Tool & Gauge (Chamber reamers) 598 Avenue C Medford, Oregon 97503 Telephone: (541) 826-5304
THE OLD AND NEWER WINCHESTER MODEL 88 RIFLE AND CARBINE
BY BERNARD H. DIGIACOBBE, M.D.
AND GEORGE E. DVORCHAK JR., M.D.
PHOTOS BY GEORGE DVORCHAK
On examining the Winchester Model 88, it becomes obvious even to the non-collector that its concept and design were advanced for a rifle that was first introduced back in 1955. Previously, lever action rifles were restricted to low pressure cartridges and further limited to the use of blunt-nose bullets which shed velocity faster than “pointed’ varieties. These bullet types were what could only be safely used since there was obviously a safety concern of “pointed bullet tips on primers” in the tubular magazine varieties of lever action carbines. In addition, most of these earlier designs were ill-suited to the use of telescopic sights. One notable exception was the Savage Model 99. While this design with its rear lock-up was already over half a century old, it could handle, or more importantly extract, such high pressure cartridges as a .250-3000 (now simply called the .250 Savage) and .300 Savage. It was also readily adaptable to the use of a scope mounted to the top of its action. This lever action thus became an increasingly popular choice with hunters and was in a position to challenge Winchester’s domination of the level action rifle market at that time.