Editor’s Observe: One present fad amongst outdoorsmen is to bash 6.5mm cartridges, with the 6.5 Creedmoor being the actual goal of ire for this vocal minority of malcontents. However the emergence of that cartridge, and the additionally spectacular 6.5×47 Lapua and 6.5 PRC had been no accident. There had been a rising development for many years to provide you with the very best 6.5mm cartridge that leveraged the latest developments in ballistic know-how. With higher powders, bullets and a refined sense of cartridge design, accuracy-obsessed riflemen, like my predecessor as Outside Life’s capturing editor, Jim Carmichel, had been pushing the boundaries. This story particulars his growth of the 6.5 Leopard and a few earlier efforts with 6.5mm cartridge wildcats. Outside Life first revealed this story in 2005, two years earlier than the 6.5 Creedmoor was launched. One fascinating factor concerning the Leopard is that it anticipated the arrival of each the 6.5 PRC, which is a consummate long-range cartridge for capturing metal and is among the best open-country searching rounds accessible right this moment, and the 6.5 SAUM, which is one other short-fat 6.5 magnum that has its virtues however is already fading within the 6.5 PRC’s shadow. —John B. Snow, capturing editor
Nothing makes the guts of a confirmed wildcatter beat sooner than the primary time he sights-in a brand new cartridge. The push of adrenaline is introduced on not by the cartridge itself however by the attainable methods wherein the case could be squeezed, inflated, minimize off, necked up or down or in any other case mutilated.
Come to think about it, response could also be just like the palpitations of a frat boy at spring break upon viewing a sunny seashore glowing with bikini-clad nymphs. This gorgeous properly sums up my response on the first glimpse of Winchester’s .300 Brief Magnum. However reasonably than speculating on varied methods to change the case, I knew immediately what I meant to do with it. It was nearly as if the pudgy little case was chatting with me, saying, “Sure, let’s do it. I’m only a plain-Jane .30 now, however in my coronary heart I actually wish to be an attractive six and a half millimeters!”
The scene was a searching membership within the wilds of Arkansas the place some massive pictures from Winchester ammo and Browning Arms had gathered a bunch of gun writers to preview the Brief Magnum cartridge and attendant rifles with which they had been to stun the capturing world a number of months later. After a number of rounds of capturing I collected a small bagful of fired WSM circumstances, which might change into the nucleus of my first experiments with the WSM necked down to six.5mm.
I’m within the behavior of giving my wildcats cat-themed names, starting with the racy .22 CHeetah, adopted by the 6mm CHeetah, the .260 Bobcat, the .264 Panther and the .243 Catbird that Kenny Jarrett and I labored on collectively. However what to name this newest?
There was a reputation I’d been saving for a brand new cartridge that possessed a particular feline mix of velocity and accuracy, and as load growth and vary testing progressed it turned apparent to me that this was the spherical that deserved to be named after the quickest and deadliest cat of all-the leopard!
However why 6.5mm as an alternative of, say, .25 caliber or 7mm? Merely put, the 6.5 (.264 inch) stands alone and other than different calibers in its class. Traditionally, 6.5 cartridges have been loaded with bullets which have a very excessive weight-to-diameter ratio. Army cartridges, such because the 6.5×52 Italian Carcano, 6.5×50 Japanese, 6.5×54 Mannlicher and 6.5×55 Swede, are sometimes loaded with bullets within the 160-grain weight vary.
The excessive sectional density of those 6.5 bullets tends to offer them nice retained velocity and power, higher wind resistance and deeper penetration. Because of this the little 6.5×54 M.S., loaded with 160-grain full-jacket bullets, was a favourite of {many professional} elephant hunters. From an accuracy standpoint, varied 6.5 cartridges dominated 300-meter Olympic rifle competitors for a few years, and the 6.5 is more and more widespread in right this moment’s medium- to long-range competitors. On account of these successes within the subject and on course ranges, there’s a excellent assortment of 6.5 bullets accessible to the handloader and experimenter, which, after all, makes the 6.5 particularly enticing to wildcatters similar to myself.
The 6.5 Cartridge Story
Cartridges of 6.5mm caliber have been round for over 100 years, with the old-time favorites being joined extra lately by the more and more widespread .260 Remington. And there’s additionally nothing all that new about makes an attempt at “magnumized” 6.5’s made by the ammo trade and wildcatters. If we dig again all the best way to 1913 we discover that the Western Cartridge Co. loaded a 6.5 spherical referred to as the .256 Newton, for which a muzzle velocity of two,760 fps (toes per second) with a 129-grain bullet was claimed. Newton was a well-known wildcatter and experimenter of his period, and his .256 was merely the .30/06 case reformed and necked to .26 caliber. Since then there was an countless stream of 6.5 wildcats primarily based on the ’06 case and most of them are fairly good.
Again earlier than World Warfare II, the German ammo agency of RWS listed a scorching 6.5 spherical referred to as the 6.5×68, for which it claimea velocity of three,450 fps with a 123-grain bullet. A handful of rifles on this caliber had been imported into the U.S., however usually talking the 6.5 caliber (and most different European “metric” calibers) didn’t excite American sportsmen-an angle that continued to prevail when Winchester launched its .264 Win. Magazine. again within the Nineteen Fifties.
By all reckoning, the .264 Winchester Magnum ought to have been a smash hit. It had a belted case, which was all the craze then, and claimed a scorching 3,700 fps velocity with 100-grain bullets and three,200 fps with 140-grainers. These velocities had been presumably from the 26-inch barrels of the M-70 rifle Winchester referred to as the “Westerner.” However the 6.5 curse held agency and Winchester’s nice expectations withered.
A fair sadder 6.5mm story is the misbegotten 6.5 Rem. Magazine. launched again in 1966. I say misbegotten due to the just about comedian mismatch of the cartridge and stubby-barreled Mannequin 600 Remington rifle with which it was paired. Speak concerning the odd couple…
So, given the continual failure of previous makes an attempt at a “magnum” 6.5-caliber, why ought to I be taken with the notion to offer it one other attempt? Really, there are a number of good causes, starting with the truth that the timing, situations and demand are upon us. Anyhow, I’ve been smitten with potentialities of 6.5 bullets ever since I started experimenting with them a number of years in the past. [BRACKET “See “The Ultimate Caliber,” September 1995, and “The Best Deer Cartridge Yet?” January 1997.”]
In the meantime, one other 6.5 wildcat, primarily based on the .284 Winchester case (which lately turned referred to as the 6.5-284 Norma when the Swedish agency started making devoted brass) has been having appreciable success in long-range goal competitors. With bullets within the 140-grain vary, the MV (muzzle velocity) of the 6.5-284 is round 2,900 fps. Clearly, this can be a velocity enchancment over the extremely correct however slower .260 Remington, one other goal and searching favourite that maxes out at about 100 fps slower.
A New Concept
However why not make a much bigger soar, say to about 3,200 fps with a 140-grain bullet? The flatter trajectory and lowered wind drift of the higher-velocity load could be a particular benefit for longer-range searching and goal capturing.
Through the golden age of wildcatting, experimenters had solely to look to .30/06 and belted magnum circumstances for inspiration. Therefore, the 6.5/06 in its many incarnations and critical barrel scorchers such because the 6.5-300 WWH, which is the .300 Weatherby necked all the way down to .26 caliber. However these days are fairly properly previous, with present considering targeted on accuracy in addition to velocity, particularly the “fat-and-short” case idea. Because of this the rotund and conspicuously beltless .404 Jeffery case has been the mom of a number of new caliber configurations of late. (Often by merely shortening and necking all the way down to a wide range of calibers.) In different phrases, the .404’s higher physique girth yields higher propellant capability than a typical H&H-type; belted case of the identical size, or, thought-about one other approach, equal capability in a shorter kind.
It is a idea that enthralls apostles of accuracy as a result of, in line with present ballistic considering, a quantity of propellant ignites and burns extra uniformly in a brief, fats case. There may be ample proof to help this, most notably within the squatty “PPC”-type cartridges which have dominated benchrest competitions for the previous a number of years. Necking the .300 WSM case to six.5 is completely in tune with this development in that it might duplicate the exterior ballistics of, say, the .264 Win. Magazine., however with an added accuracy bonus. Plus, the shorter spherical would additionally match shorter and stiffer rifle actions, yielding a double accuracy bonus.
Delivery of the Leopard
Clearly, necking the spanking-new WSM case down to six.5 caliber was a wildcat simply begging to be born. However constructing a wildcat from scratch is significantly extra difficult than it sounds, particularly when there aren’t any current chambering reamers or loading dies. So my first transfer was to ship samples of the WSM case to JGS Precision Software Firm in Coos Bay, Ore., which has made chambering reamers for my different wildcats. The parents there made drawings of the proposed cartridge and floor units of reamers for making loading dies and for chambering barrels. In line with my idea, the size of the WSM had been to stay the identical apart from the smaller neck. Loading dies for the proposed spherical, which I then referred to as merely the 6.5-300 WSM, had been made by Redding, and a well-lubed .300 WSM case may very well be necked down in a single operation. Since then, .270 WSM brass has change into accessible and is even simpler to neck down.
The following step within the course of was chambering and becoming a take a look at barrel with a heavy, 26-inch, air-gauged, XX-grade Douglas barrel. The barrel has a 1-in-9-inch twist and was fitted to a Remington M-700 quick motion and the bolt was modified for the bigger WSM rim.
Throughout wildcatting’s heyday, only a few handloaders had entry to-or even data of-the costly and complex pressure-measuring gear used within the ammo trade’s labs, so stress was “measured” by flattened or blown primers, bolt raise and different primitive means.
These days, nevertheless, because of the Oehler M-43 PBL (Private Ballistic Lab), critical experimenters can measure pressures and thus keep away from the earlier pitfalls of wildcatting. The PBL is moveable sufficient to be carried to the capturing bench and versatile sufficient to measure and report velocity and stress whereas on the identical time permitting take a look at firing for accuracy. Because of this an M-43 was used all through growth of the 6.5 Leopard.
So simply how fast is that this Leopard? And the way correct is it? Regardless of predictions on the contrary, the accuracy of Sierra’s 142-grain Match King bullet really tended to enhance as velocities elevated. At 100 yards, five-shot teams of a half inch or so had been routinely on the 3,200 fps stage, and lighter bullets additionally did their finest at prime velocities (see chart). However keep in mind, these small teams had been fired with an correct, heavy-barreled take a look at rifle below supreme situations.
Will the 6.5 Leopard be tailored by mainline ammo and rifle makers or will it ceaselessly stay a wildcat? My finest guess is that one thing equivalent or related is already within the works. Remington’s 7mm Brief Motion Extremely Magazine. cartridges, for instance, could be a superb automobile for a 6.5. And are available to think about it, an organization with a “magnum” custom, similar to Weatherby, would do properly with this or an identical cartridge in a short-action Weatherby rifle. Good wildcats have a tendency to show up in manufacturing unit gown, so we’ll know in a yr or so.
