First, There Was the .338 Bin Magnum

IT STARTED for me in 2003.  I was in a flurry of building custom rifles at the time, an affliction well known and shared by many of my Campfire cohorts (if you have not caught it yet, just stick around), and I "needed" an elk rifle.

Now, this elk rifle could not be the eight-pound .30-06 Ackley Improved that I had specifically built as an "all-around" rifle — capable of taking everything in North America except the big bears.  My five-and-three-quarter-pound .308 Winchester was not elky enough, either.  That was a "sheep rifle," you see.  My factory Winchester Model 70 Supergrade in .300 Winchester Magnum was too heavy, at nine-plus pounds, for any reasonable man to be expected to carry it up and down the Rocky Mountains, and my other custom .300 Winchester Magnum, with its twenty-six-inch barrel, would not do either — not handy enough for a quick shot in the timber.

Left to right: the .375 H&H Magnum, .375 Ruger, .338-.375 Campfire, and .338 Winchester Magnum.

I share my thought process in order to illustrate the "contemplative" state of mind that leads an ostensibly normal, sensible hunter to conclude that a .338 Winchester Magnum is not an optimal chambering for a semicustom elk rifle.  After all, if a .300 Winchester Magnum, with ninety or more grains of case capacity, fits in a standard-length action, why did the designers of the .338 Winchester Magnum shortchange us with only eighty-six grains of case capacity with the .338 version of the same shortened Holland & Holland case?  A heavier bullet requires more powder, right?  Of course it does.

In fact, what I needed for my "ultimate" elk cartridge was a fully blown out cartridge with a 0.532-inch rim and head diameter (to lend itself to easy conversion from factory-chambered belted-magnum rifles), that would fit in — and fill — a standard-length action.  Therefore, a forty-degree Ackley-esque shoulder angle and a minimal neck length would also be required.  A beltless case with a 0.532-inch head diameter would allow a designer to squeeze in a few more granules of powder into each case and eliminate the unneeded belt.  I was going to build "the ultimate elk rifle" (all rifle cranks are building the ultimate something rifle for their next project, which makes one wonder why these pinnacles of vision and technical execution rarely fetch fifty cents on the dollar when they are inevitably sold (usually to partially fund the next wonder rifle)).  I wanted to have the ultimate elk chambering.  Nothing that the factories were putting out was up to the task!

I must point out that I reached these conclusions completely on my own.  Nevertheless, I set out to consult with an expert who – I was certain – would agree.  Ken Howell, Editor of this magazine, has designed a cartridge or two and is the author (and illustrator) of Designing and Forming Custom Cartridges, an authoritative treaty on the subject.  He undoubtedly has forgotten more about this sort of thing than I am likely ever to know.

Ken politely suggested that I ought to consider the poor feeding properties of a basically straight-walled cartridge with a sharp, forty-degree shoulder angle, and maybe consider why a too short neck could give me problems with certain heavy-for-caliber bullets.  Also, had I considered how readily available my parent brass might be?  Did I know that no rimless, beltless, standard-length cartridge case with a 0.532-inch head diameter existed?

Now there was a stumbling block!

The original .338 Bin Magnum.

Ken patiently explained to me that I had basically two options.

The first was to use .404 Jeffery brass, with a head diameter of 0.537 inch and a length of 2.860 inches.  Of course, this would require annealing case shoulders (requiring effort), then running the cases through forming dies (requiring money), then through sizing dies (requiring more money), then trimming to length (requiring effort), then deburring (requiring more effort).  Ken mentioned that my case necks might be thick enough to require inside reaming (more money and effort), but he could not be sure until we had the sized cases in hand.  It sounded like a lot to consider, all right.

The good news was that the late Don Allen, founder of Dakota Arms, developed his .330 Dakota (the first of six cartridges that he based on the .404 Jeffery) along these same lines, and I could therefore simply chamber my ultimate elk rifle in .330 Dakota and buy .330 Dakota brass from Dakota Arms.

I was not satisfied.  I "contemplated" the rim diameter.  Dakota's .330 has a rim and head diameter of 0.545 inch — even larger than the .404 Jeffery, and despite Ken's assurance that there was enough slop built into most factory bolt faces to allow for the operation of a case with an extra thirteen thousandths of an inch rim diameter every time, I was uncomfortable with a design with the built in potential to misfeed when chambered in a standard factory action.

The only solution was to modify the donor rifle's bolt face (requiring money), or use a factory Dakota action (requiring more money), both viable options, but neither in line with my notion of easily rechambering a standard factory belted-magnum action.

Just to cover my bases, I went online and checked the price on .330 Dakota brass, and it turned out that they required money too ($2.00 per piece).  And so, with a typical shooter's budget firmly in mind (and in wallet), I chucked the idea of the .330 Dakota.

The second option was to use 8x68S brass.  The 8x68S is a fine cartridge, and brass was readily available from RWS.  The 8x68S has a case length of 2.657 inches, a rim diameter of 0.511 inch, and a head diameter of 0.523 inch.  Forming it to acceptable specifications would require necking it down and then fire-forming — not too objectionable.

However, the 8x68S case also had issues.  The head diameter of 0.523 inch negated the extra case capacity I wanted; the ultimate case would have a head diameter of 0.532 inch (and its accompanying larger internal volume).  Moreover, while the 8x68S eliminated the belt, leaving a rebated rim (diameter of 0.511 inch) in my wildcat was not what I had in mind.  Further issues like the fact that 8x68S brass was not designed with modern chamber pressures of 60,000 pounds per square inch in mind sealed the deal.  The 8x68S would not do, either.

In the meantime, Ken had quietly designed a case for me that incorporated most of my requirements for the ultimate elk cartridge, although seasoned with some of the savvy that experience had taught him.

Ken used the Jeffery case and, but kept the overall length at 2.5 inches, and his shoulder angle was a modest twenty-five degrees, and the (too long) 0.375-inch neck wasn't on my hot-rodder list either.

Add to that the "hassle factor" — as well as the cost of reamers, dies, and brass — and by then my enthusiasm for the ultimate elk chambering had been quelled.

But the .338 Bin Magnum had been conceived — as only an AutoCAD image on Ken's computer hard drive, but conceived, nonetheless, and awaiting gestation and birth.

Then Along Came Ruger and Hornady …

At the 2005 SHOT Show, as I was making the rounds of all the usual suspects, the rumor reached me that Hornady and Ruger were planning to announce a new cartridge.  Like many others, I assumed that it would be something small, in the lineage of the vastly successful .204 Ruger.

A couple of weeks after the SHOT Show, however, as I made the obligatory post-show telephone rounds, I stumbled upon rumors of actual case dimensions, and my jaw dropped.

Here was the perfect case on which to build my back-burnered ultimate elk cartridge.

Reamer specs for the .338-.375 Campfire.

I knew that there can often be a long wait between the time when a new rifle model or factory chambering is announced and the time when the announced product actually arrives on dealer shelves.  My project could not begin until I could get brass!  Nevertheless, I began to keep my nose in the wind for all the other necessary components, to eliminate undue delays once the brass would become available.

First, as Ken advised, I contacted Dave Kiff, of Pacific Tool and Gauge.  Dave agreed when I told him of my ingenious idea of modifying the .375 Ruger by simply necking it down, and all of the benefits that such a simple modification offered to wildcatters and rifle hot-rodders.  In fact, he said that because of a unique set of circumstances, he might be able to get me a reamer in record time, about as fast, it turns out, as if he had the reamer already made and on the shelf!  Since Dave so liked the project that he was inspired to create the reamer "yesterday," I felt that the project had legs.

I then contacted Mickey Coleman of Coleman Rifles.  I know that Mickey's reputation keeps his services in great demand, and a prior .257 Weatherby he had built for me had proven to shoot lights-out, so I intended to "get in line" as early as possible.  Mickey was enthusiastic about building the rifle, and even mentioned that he might have a perfect Remington 700 action for the project.  When he heard the case dimensions, he chuckled and let me know that shooting the rifle would be up to me.

So, I had now a ready chamber reamer, a willing gunsmith, and a standard, factory Remington 700 action chambered in a magnum caliber, with the appropriate bolt-face diameter (and feed rails) — just the type of action that I hoped would be easy for anyone to chamber to the .338-.375 Campfire.

Before long, I found myself on the telephone with Dan Wynne, formerly of Montana Rifle Company and now of McGowen Precision Rifle Barrels.  Dan and I were discussing another rifle project in which we had both been involved when I mentioned that a current "top-secret wildcat" excited me.  It was not long before Dan and McGowan agreed to provide a Number-4-contour, chrome-moly barrel with a 1-in-10-inch twist for the project.

The ultimate elk rifle would require more than just the ultimate chambering.  In contemplating the rifle's operation in the thick black timber that elk regularly inhabit, I remembered a bolt modification done by Karl Feldkamp at Kampfeld Custom for a .257 Weatherby project.  Karl graciously agreed to install the same custom "Campfire" oversized bolt handle on the .338-.375 Campfire, as well as to stylishly flute the bolt, for a bargain price.

Now my project was really rolling.

Next, I ordered a stock from McMillan Fiberglass Stocks, a Remington Classic in standard fiberglass construction with standard fill, inletted for right-hand long-action Model 700 with a blind magazine (ADL).  It would arrive at just about the time the .338-.375 Campfire barreled action would be coming together.

With most of the major pieces of the rifle accounted for, I needed to arrange for ammunition.  I made the rounds of various reloading-die companies to inquire about dies and found that making custom dies was a months-long affair.  Dave Kiff recommended that I contact Jim Carstensen, of JLC Precision and that maybe Jim could set me up more quickly.  Sure enough, I contacted Jim, and within a matter of a few weeks, I had a custom neck-sizing die and seater that I could use to fire-form cases.  In the meantime, I ordered a set of Hornady dies — full-length sizer and seater — and sent them to Jim for his custom conversion.  Jim modified the sizer die to accept a collet of the right diameter, and I now had the dies.

Soon thereafter, I found myself in an email exchange with Coni Brooks at Barnes Bullets, and I mentioned to her that I wanted to use Barnes monolithic TripleShock bullets.  Coni agreed to send me some TripleShock bullets.

Now I needed brass.  After a few unsuccessful tries at backordering from major suppliers, I posted a request for .375 Ruger brass or loaded ammunition here at the Campfire and began the wait.  Before long, someone here promised to deliver both brass and loaded ammunition in exchange for my promise to never reveal his identity, and for some credit for future Campfire purchases.

I contacted Ken again for loading data for my new wildcat.  Ken had me carefully measure the case capacity of my unfired and necked-down cases by filling them with water "so that the meniscus is over the mouth."  He also had me measure the length of the Barnes 225-grain TSX bullets, as well as the overall length of my chamber as measured from bolt face to lands.

Ken ran these figures through QuickLOAD, the excellent interior- and exterior-ballistics program produced by NECO, and gave me some starting loads with Ramshot Magnum powder, which Ken described as an optimal powder based upon the ratio of case volume to an anticipated pressure maximum of about fifty thousand pounds per square inch.

The summer waned into the early fall, and with a Colorado mule-deer hunt planned for early November, I was very pleased that my turn in line at Coleman Rifles came up when it did.  I received the rifle about three weeks before I was to leave for that hunt and was able to squeeze in a pillar-bedding job and a hasty range session.  The latter confirmed that Ken's preliminary load data would, in fact, keep the rifle from exploding with the first trigger pull.

Not only that, but as I increased powder charges one grain at a time the groups with Barnes 225-grain TSXs shrank to well below one inch, then began opening up again a few grains below Ken's recommended maximum charge.  I returned to the "sweet spot," and sure enough, groups were tight and round.  Two consecutive sub-MOA groups at two hundred yards convinced me that the rifle was a hunter, and with a lot of load development yet to do, I happily took my zeroed-in rifle and single sub-MOA load home to prepare for my hunt!

And I will tell you all about the rest of it when I get home.

To be continued …

Ask Rick Bin Questions About the .338-.375 Campfire

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