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Rocky’s Reloading Room |
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LOADING FROM SCRATCH
For reloaders, the best advice ever given is to strictly follow the instructions and data provided in current loading manuals. A prudent handloader will neither go beyond recommended load recipes nor invent combinations not listed. In handloading, it is axiomatic that untrod territory is a land of danger. But what are reloaders to do when there is no published data for a given cartridge? Whether it's a wildcat caliber, an obsolete cartridge or one that simply isn't popular, there are many reloadable cartridges for which data doesn't exist or isn't at hand. Just how do we develop load data from scratch?
Over the past few years, that's exactly what I've been forced to do. Not just for one oddball round, mind you, but for several entirely different ones. How I managed to safely do so is a lesson from which every reloader can learn, even if he is involved in only well established cartridges. Why? Because the processes I followed are really no different than in working up loads for any caliber. Picking efficient powder and bullet combinations and measuring load performance are part and parcel of all reloading. When working from scratch, those aspects simply take more research, more caution and more attention to detail.
The four common elements to all load development are: 1. Find the best available, current load data from several sources if possible; 2. Pick components best suited to safe, efficient performance in that cartridge; 3. Start with the lightest loads compatible with the powder selected; and 4. Use every pressure and performance indication available during testing.
Once again, it's important to realize that the above are procedures to follow with all reloading, not just when loading from scratch. Even with standard, commercial rounds, my first step with a new rifle is to fire at least ten fresh factory rounds. At the range I record velocity, standard deviation and accuracy plus notes on functioning, ease of extraction and more. At home I carefully measure each fired case for expansion (more on this below), then average the results. I record all these data as baselines for that round in that particular gun.
Before I select powder and bullet combinations for reloads, I review every bit of literature I can find on that caliber. I'll review all current loading manuals for the powders and bullets I'm contemplating, any magazine articles in my collection, plus any other published data in my extensive reference library. I'll select the pet loads most frequently mentioned in a variety of publications and by various authors.
Next, I'll crosscheck that data with Wayne Blackwell's excellent computer software, "Load From A Disk." This unique program actually computes optimum powder/bullet combinations for any existing or even imaginary rifle cartridge. Computed are ideal and alternate loads, with predicted velocities and chamber pressures. Based on the famous Powley equations and others, it's amazing how accurate actual results compare with LFD predictions.
Next I prepare individual load sheets for each powder and bullet combination. With a separate line for each incremental powder charge increase, these sheets allow me to track progressive changes in velocity, case expansion and accuracy. I work each combination up to maximum in that rifle, or until it becomes obvious that the gun doesn't like it. To save on paper, I use my computer to store all these preliminary load sheets. When each load combination is completely tested, I combine the best loads onto a single sheet and print it out for insertion into a binder. The binder is what I keep in my loading room for future loading sessions. In case I ever need to refer to the original data, they are stored on floppy disks. Such volumes of data come in extremely handy in the event that particular powders, primers or bullets are discontinued or become hard to find.
If that should happen, chances are there's a nearly-as-good combination I've already tested using available components. With that knowledge, I won't have to waste possibly precious items in duplicating work. It's also the reason I constantly experiment with new or different components, even though I may have already found a pet load for a given rifle.
To give an idea of how to follow the four steps listed above, let's trace my steps in the development of two very different cartridges. One is a small but potent pistol cartridge and the other is a little known high intensity wildcat rifle cartridge. The first is the 9mm Makarov and the second is the .25-308, also known as the .25 Souper. Because I worked first with the Makarov, I'll detail that story first. Almost unknown and virtually unobtainable during the Cold War years, the 9mm Makarov is the standard military service round of most former Communist countries, and also serves as a police round in those same parts of the world. Now widely available to U.S. shooters, pistols in this caliber are finding much favor for their low cost, high reliability and respectable power considering their small size.
But except for imported military ammo, much of it corrosive, there wasn't anything to shoot in these finely made guns. So I began to research the round for reloading possibilities. Careful measurement showed that fired brass had almost exactly the dimensions of regular 9mm Luger (Parabellum) cases, except for being slightly shorter and without the prominent body taper. Simply trimming regular 9mm brass to an overall length of 0.700" would result in a plentiful supply of brass. But that still left me in the dark about load data. Following the first rule about finding current data, I turned to my reference shelf. Virtually the only reference to the 9mm Makarov was found in the classic tome "Cartridges of the World" by Frank Barnes.
Barnes describes the Makarov as being between the .380 ACP and the 9mm Luger in size and performance, having about 10 percent greater case capacity than the former and less than the latter. The listing also gives a recipe calling for 5.0 grains of Unique under a 100-grain jacketed bullet. That is much heavier than published loads for the .380, but I thought I'd surely be safe with a load from the highly-respected Barnes.
I wasn't the least bit apprehensive when I touched off the first of these loads - a mark of my naiveté. But that confidence was immediately shattered. Recoil and blast were much heavier than the military loads I'd fired. Shaken, my gaze flew to my Oehler chronograph. Instead of the 1100 fps reading I expected, the digital printout said 1378. From a blowback-operated pistol! I immediately counted my trembling fingers, unloaded the pistol and returned home for some soul-searching.
Another look at Barnes revealed what I should've picked up before: the load listed for the Makarov had been reported to Barnes, but Barnes hadn't verified it; indeed he had never fired a Makarov. Wherever that imaginary load came from, it definitely is grossly excessive in a real-world Makarov. Or maybe it was a Commie plot to rid Western shooters of their extremities. Obviously, my error had been in sloppy research, coupled with overconfidence and lack of prudence. I resolved to expend more caution than gunpowder in the future.
My next loads used proven .380 ACP data. Because the Makarov has greater case capacity and uses bullets of identical weight (but not diameter), I believed these would be safe. And they were. Still, it was with some trepidation that I touched off the first of them! With these loads and fired factory cases as a baseline, I could now start advancing the throttles. To go beyond this point, I used proven techniques to measure pressure and velocity. Because it is the primary determinant of a safe load, I concentrate on pressure.
By carefully measuring just ahead of the extractor groove, I first determine expansion of fired factory cases. This averaged 0.3935-inch in cases from my Makarov. This measurement doesn't reveal actual firing pressures, but does allow you to track case expansion caused by pressure and compare it to a standard. Careful measurements reveal when handloads approximate the working pressures of factory ammo in a given gun.
By the way, I don't take credit for this technique. It is fully described by Ken Waters in his classic series "Pet Loads, Vol I and II," another must-have reference work for any serious reloader. I have found Ken's technique to be a usable and accurate pressure indicator, much more objective and reliable than primer appearance. For blowback pistols, I consider expansion of 0.0005 above that of factory rounds as maximum. For my individual Makarov pistol, therefore, reloads which expand cases to 0.3940 are absolute maximum.
Like many reloaders, I also monitor chronograph results to help determine maximum loads. While working charge weights up slowly, I record then graph velocity averages and standard deviations. When velocity increases start to level off even though the charge is being increased in identical increments, that's maximum. Usually, that's also about the point where velocity standard deviations and group sizes get dramatically larger. Considered together, case expansion, velocity plateau/consistency and accuracy deterioration are clear indicators of a maximum load. Not to be ignored are other indicators such as extraction difficulty, short case life and primer appearance. A sudden change in any one of these factors is a red flag that things may be getting close to max. Two or more and you've almost certainly crossed the safety threshold.
Back to the Mak. Having found one safe load, I next studied .380 ACP load data for other efficient powders. In careful and very conservative steps, I worked up loads for nearly a dozen different powders and several jacketed and cast bullets types. These results were published in American Rifleman magazine (Dec, 1993). I now have a pistol that is reliable enough for a carry gun (with factory ammo for legal reasons) yet can be safely and economically reloaded for plentiful practice.
In many respects, small handgun cartridges are much more difficult to load from scratch than rifle rounds. Small case volume combined with powders of very fast burning rates mean that even tiny variations in powder charges, bullet seating depth or other factors can result in wide pressure swings. There are also no proven ways to predict performance with mathematical formulae, or software based on those formulae. Fortunately, rifle rounds are easier to develop.
An example is the .25-308. The .308 Winchester was introduced to civilian shooters in September, 1952. Immediately thereafter, it was necked up and down to almost every available bullet diameter from .224 through .358 by that era's ardent wildcatters. Several of those wildcats have gone on to considerable fame and commercial adaptation, such as the .243 and .358 Winchester and the 7mm-08 Remington. Others like the .220 Jaybird have many avid users but have not yet been commercially chambered. Still others blossomed but withered on the vine for no really good reason.
Among the latter is the .25-308, also known as the .25 Souper. Reportedly first developed by one P.F. Lambert of Washington DC, it surpasses the vaunted .257 Roberts in both velocity and accuracy and nudges close to the justly famous .25-06. And it does so with smaller doses of powder and in short action rifles, in which neither of its more famous big brothers will fit. In those short actions, it produces significantly higher performance than the .250 Savage. It shares none of the sometimes unreliable bullet expansion characteristics of the .243 with less recoil and blast than the 7mm-08. So why isn't it better known? It beats me.
But I was attracted to it for one very simple reason: I couldn't find a bolt action .250 Savage. I work in a very well stocked gun shop and attend gun shows all over the Western states as an ear protection vendor. Despite this exposure, I looked unsuccessfully for more than two years for a nice .250 Savage bolt gun. Not one showed up. Deciding to rebarrel one of my two Remington 788 rifles in .308, it occurred to me that the .25-308 wildcat would allow me to use plentiful .308 brass as well as my existing stock of removable magazines. And so I began research.
One of the advantages of working in a half-century-old gun shop is that there are occasional treasures back in the musty dusties. One of the treasures I uncovered was a copy of Speer's unique Number 4 loading manual, published in 1959, and the only one ever devoted entirely to wildcats. And right there on page 67 is the .25 Souper, with loads for four bullet weights and using eight different powders. That was the good news.
The bad news was that one of those powders, Hi-Vel 2, is no longer around. Worse, loads using 4831, 4985, 3031 and 4350 were certainly based on war surplus lots known to perform differently from the powders of the same numbers we load today. Nor are the bullets used then of the same jacket material, friction coefficient or bearing length as today's. And, as I'd learned with the Makarov, some data isn't always better than none. So I turned to my computer. My copy of Load From a Disk software prompted me for parameters such as case volume (of water), bullet length and weight, barrel length, overall cartridge length and the like. Out popped several recommended powders and charge weights, predicted velocities and pressures. Then I had LFD print out sheets of similar data on the .243 and 7mm-08 cartridges, for comparison.
It was quickly apparent that loads for the .25 wildcat fell neatly between its two stable mates using similar or identical powders. I verified this with a half dozen loading manuals and with published articles on the two commercial rounds. I also looked at loads for the .250 Savage and .257 Roberts. Although they are based on very different cases, their case volumes could be compared and relationships between load data examined. If it's beginning to sound like I spend a good deal of time and effort on research, you are right. After all, this is not only fun in itself, it's the only non-hazardous stage of reloading.
When my rifle was finally complete, it was time to begin actual loading. With the rifle came two fired test cases, which I used to adjust my sizing die and record fired expansion diameter. I'd already obtained a set of RCBS dies (out of their normal stock no less!) and prepared a lot of new brass by sizing, trimming to length, uniforming flash holes and the like. For my first loads I selected a bullet of 75 grains and one of the LFD recommended powders. I chose IMR 4895 for its documented consistent performance at well below full throttle charge weights. Start level loads also filled my cases to more than 85 percent of capacity, a known inducement to efficiency and consistency. Starting at the lowest of the charges recommended by my computer printout and increasing in two grain increments up to just under maximum levels, I produced five cartridges of each load.
To say that all my preparation was successful would be something of an understatement. The first five rounds resulted in mild recoil and blast, effortless extraction, respectable velocity and cases expanded to smaller maximum diameters than the two test cases. I cleaned the barrel and let it cool. The next test load used 43.0 grains of 4895. The first shot from the clean barrel was wide but the next four went into a group of .313-inch at almost exactly the velocity predicted by LFD. That is one of the best groups I've ever fired. To have it happen with an unknown wildcat from a brand new barrel and with only the second test load is astounding.
Whether you're contemplating a wildcat of your own design, working with an existing but little known caliber or just trying new combinations of components in the old reliable "aught six," the same basic four rules of reloading will keep you safe and your firearms in one piece. The reloader's path may occasionally be untrod, but the steps are familiar. Article published in Handloader’s Digest, 16th Edition, 1997 |