AFRICA HUNTER QUEST©    

     Chapter 25 - THE PILGRIM DISCOVERS THE ZEN OF ACCURACY    

     Donny loaded his truck late Tuesday afternoon and was on his way to the range before sunrise on Wednesday. GG was at his usual bench, this time with what appeared to be a short action hunting rifle perched on a bipod and a beat-up rear benchrest bag. Donny could see an insulated cup sitting on the bench, possibly indicating GG’s focus this morning was less intense.    

     Once again, the Old Man’s radar picked him up as he walked toward his bench. GG turned to face him.    

     GG:    Ready to go?    

     D:    I ginned the ammo the way you asked and brought the tools you wanted. I’m ready to apply your methods to my accuracy quest.     

     GG:    Did you load up brass previously fired in your chamber? If not, we need to abort. The technique I’m going to show you isn’t worth beans unless it is done with fire-formed brass.     

     D:    Yes. All once-fired in my chamber.    

     GG:    Good. Rig your stuff on my table. After you do, I will give you the conceptual overview of how I go about load development.     

     Donny had noted that there were only three things on the table: GG’s range box, a relatively large three-ring binder, and a pathetic-looking particle board gun vise that had been clamped at one end of the table. Donny unloaded his tools and ammo, then clamped his press to the table. He then arranged his tools and ammo neatly on the table next to the press. He was ready.    

     GG:    The best advice anyone ever gave me was from Skip Talbot. I asked him how he did load development. He gave me a one-sentence reply:     “Find the maximum pressure, then back off half a grain and tinker with the seating depth.” That’s the fundamental basis of the load development approach I will show you.    

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     Donny knew it couldn’t be that simple, not with the stuff he had brought to the range. That, and he didn’t believe GG did anything based on ‘simple’. The Old Man paused and smiled ruefully. “Yep,” thought Donny. “He’s about to turn on the fire hose.”    

     GG:    Before I begin, I want to pay homage to Ol’ Skip. He was pretty much dead nuts on. I suppose if he and I could agree on what he called maximum pressure, there would be no ‘pretty much’ to it. It would be a ‘bingo’. All my loads are within spittin’ distance of pressure that I have defined as maximum, based on extractor groove expansion.    

     D:    Extractor groove?    

     GG:    The indentation between the case rim and the case body.    

     D:    It expands?    

     GG:    Yes. A loose primer pocket is a primary indicator that the extractor groove has unacceptably expanded. An expanded extractor groove means the design stress of the brass has been exceeded. All brass is manufactured to withstand a specific maximum stress before the brass yields, and by yield I mean permanently deforms. With the 270 Winchester brass, that maximum stress is 65,000 psi. That is 1000 psi more than 300 Winchester brass and 4000 psi more than 7-mm Remington mag brass.    

     D:    Stout.     

     Sir, before we dive into how you do this, I want to evict the elephant in the room. Why don’t you use a chronograph to determine velocity so it can be used as a tool to develop a load?    

     GG:    I’ve never been able to get that method to give me the competitive accuracy I needed for 1000-yard benchrest. That is why I asked Skip, one of the finest all-around shooters there ever will be, how he did it. I swallowed hard and took a chance, as he didn’t know me from Adam’s house cat. I was afraid I wouldn’t be able to understand what the man told me, let alone implement it.     

     Donny’s eyes got big, and GG saw it.     

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     GG:    We all gotta start somewhere. Figuring out who to ask is hard, figuring out if the advice you’ve been given is legit is harder, and correctly implementing what you’ve been told is the hardest. With Skip’s advice, it took a couple of years for the light to dawn with me. What he told me sounded simple, but I believe the concepts in play are high-end physics.    

     Donny audibly groaned. More hand waving to find another Goldilocks solution. But Donny still felt compelled to ask one more question about velocity. He  had to defend himself from his friends that knew a ladder test was the only method to develop a load.    

     D:    One-thousand-yard benchrest. Weren’t you concerned about velocity extreme spread?    

     GG:    Not to the point of selecting a powder. My powder selection is always based on my subjective assessment of best accuracy potential, initially determined by the methodology I am going to show you.  Based on evaluations of my 1000-yard targets, reducing any vertical at the target is more dependent on the load’s accuracy at 200 yards, the primer selected, primer sorting, brass preparation, bullet tipping, and bullet sorting than the supposed effects of velocity extreme spread at the muzzle. Besides, the instruments we shooters use are relatively crude and do not have the measuring precision to justify that focus. That and hunting ain’t long-range benchrest where tenths of an inch at 1000 yards can separate winners from also-rans.    

     D:    You said ‘best accuracy potential’. If you have multiple powders to choose from, how do you go about selecting the one that you believe is the most accurate without doing a specific load for each?    

     GG:    (Smiling) That’s what I will show you this morning. But fair warning:     the leaps of faith you made in accepting my notions of terminal performance and the empiricism I derived are child’s play compared to the leap of faith associated with accepting and implementing the load development approach I will show you.    

     D:    Sir, to paraphrase Shakespeare, there are more things in heaven and earth than I have dreamt of in my philosophy. You are the expert and I certainly am not. I’m all in.    

     GG:    Pilgrim, at least you’re willing to try. I respect that. In my view, you won’t be a successful anything, let alone a hand loader, unless you have the courage to try, particularly when there are no guarantees. Any failures are simply interim puzzles

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where you have to make an effort to get the pieces to fit or find the pieces that do. With all due respect to Yoda, trial-and-error effort is required for load development before there can be a just judgment of do or do not. Perseverance is a fundamental element of ‘do’. Lack of perseverance is a fundamental element of ‘do not’.    

     Donny’s eyes got big again. Yoda? How does the Geezer know about Yoda?!    

     GG:    Whatever scientific basis there might be to rationally explain my load development approach would probably fall under the general heading of harmonics. Within that general heading, the operational concepts I use to explain what occurs are pulse and vibrations. Pulse occurs with ignition of the primer. Assuming there is a consistent force applied by the firing pin, general things that control the pulse are the primer, powder, powder charge, flash-hole uniformity, primer pocket depth uniformity, neck tension or neck grip on the bullet, and bullet seating depth.     

     Controlling all of those things helps to make the pulse uniform. You are locked into a primer and two powders, so what will be will be. You weighed powder to the nearest 0.1 grain, the best you can do. You made the flash-holes uniform to produce a uniform flame front from the primer. You uniformed the case necks by trimming them to the same length. That uniform length contributes to a uniform grip on the bullet. You further contributed to uniforming the grip on the bullet by chamfering and polishing the interior of the case necks. You will seat all bullets to the nearest 0.001inch, again the best you can do. You will subsequently anneal the brass to produce more uniform, consistent neck grip on the bullet.    

     There are other things you could have done to the brass to make the pulse more uniform, like uniforming the primer pockets, turning or machining the case necks to a uniform thickness, and controlling the resized diameter and length that is done to the neck. I believe such steps are not really necessary to produce hunting accuracy that can be considered ‘excellent’.       

     The pulse produces all manner of vibrations in the system. Keeping the pulse uniform helps to keep the resultant vibrations uniform. Additional vibrations are introduced with travel of the bullet down the barrel. A useful analogy is the bullet acts like a bow traveling across the string of a violin. All these vibrations produce wave forms in the barrel that could either cancel themselves or amplify into harmonic resonance. Assuming the action is properly bedded and the barrel is free-floated, adjusting the pulse with incremental changes in powder charge and bullet seating depth to reduce resonance in the barrel is the primary path to accuracy.  

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     D:    I take it that cancelling all these various waves would produce uber accuracy?    

     GG:    Yes, but impossible to do. About the best anyone can conceptually hope for is a crude wave node at the barrel muzzle so that the barrel tends to spit the bullet out at the same point of barrel displacement.     

     D:    So the barrel moves?    

     GG:    Yes. Vibration produces movement. You are after consistent movement of the barrel by producing consistent pulse. Of all the things I mentioned that control pulse, which ones do you believe are the most important?    

     D:    Powder and primer?    

     GG:    Yes. Their interaction produces a time-versus-pressure curve that the system likes, tolerates, or absolutely despises. The whole idea of the first load development step I’m going to show you is to identify if your system generally likes the pulse of any of the powders you have available. If it does, I believe pursuing a load with that powder would be the best use of time and money.    

     Circumstances have locked you into just one primer and two powders. For what it’s worth, I’ve have good success with the primer you are going to use as well as with both of your powders. But at the end of the day, that track record doesn’t matter. Regardless of what you may think, the rifle always tells the truth. This morning we are going to ask it “Which powder do you prefer?” We must accept its answer and then move to the next steps in load development.    

     D:    Will the answer be obvious enough for me to understand?    

     GG:    It can be. If not, flip a coin. You will get what you get either way. All you are trying to do is take a first cut where the result can give better than Vegas house odds of success.    

     D:    When I was loading up each powder, I wondered about both the crude one-half grain progression and the loading beyond what the published maximums were for each. Is that powder loading progression somehow to back into a determination of whether my system likes the harmonics produced by these powders?    

     GG:    I think so based on what I see show up on the targets.     

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     What I will have you do to each of the cases with the progressively increasing powder charges is seat a bullet so its ogive just touches the lands. Before firing, you will measure the extractor groove of each case with the dial calipers. For each powder, you will fire all rounds at the same target placed at 100 yards. Since you have two powders to evaluate, you will have two evaluation targets. After each firing, you will again measure the diameter of the extractor groove to see if it has expanded. When you discover an extractor groove that has expanded, you know you have exceeded the case’s maximum design pressure. You then know that the maximum powder charge is somewhat less than the one that produced the expanded extractor groove.    

     D:    I get the measurements to estimate what the maximum powder charge is. I don’t see what firing all of the rounds of the same powder at the same target can tell you.    

     GG:    If the system likes the harmonics produced by the pulse initiated by ignition of a powder, you will get a reasonably small group. If the system just tolerates the powder, it won’t be small, but somewhere in never-never land. If the system hates the powder, the group will look like a shotgun pattern or even worse.     

     Donny gave GG a look of disbelief. He couldn’t help it. The notion that a load with up to 3 grains of powder difference would want to group well was beyond ridiculous. No way.     

     GG had anticipated the Pilgrim’s reaction and ‘the look’. That is why he had brought the three-ring binder. It contained the targets and data sheets from harmonics and pressure testing he had done to select the powder for his most recent hunting and target loads.     

     GG:    I know. I’ve been doing it for close to 20 years and still get slack-jawed at some of the results.     

     GG opened the binder to the first page he had paper clipped.    

     GG:    What you are looking at are the data sheets for testing I did with the 300 Winchester’s 240-grainer.     

     Donny could see that the data sheets had powder charges tabulated at 0.5 grain increments for four different powders. Extractor groove measurements were tabulated for most, both before and after the shot. Some of the data entries under the

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‘after’ column of extractor groove measurements had no numbers, only the entry NS, presumably indicating ‘not shot’. The data sheet had a column for entering velocity, but no velocities had been filled in.    

     GG:    As you can see, each of the powders I evaluated had increasing 0.5 grain powder progressions, just like you have prepared. If your case had the capacity of about a 308 Winchester, the powder progression would have been 0.3 grains. If it had the capacity of about a 221 Fireball, the progression would have been 0.2 grains. Here are the targets for each.     

     GG then opened the binder, extracted the associated targets, then placed them on the table. Donny now knew why all the Old Man’s targets were 8½ x 11:     he apparently kept the results of everything he shot!    

     Donny could not believe what he was seeing. Four-, five- and six-shot groups ranging from less than 0.8 to 2½ inches. GG had put numbers next to the impact holes on the targets to identify which powder charge was associated with each impact. Some groups were in the form of vertical lines like the one he had shot with the slower powder; some were pretty much round; and one was a chaotic spray like the one he had shot with the faster powder.    

     But there was one that knocked his hat in the creek: a seven-shot group that measured less than 0.7 inches, with six that measured less than 0.5 inches. The six-shot group was almost round. The attached data sheet verified that the powder increment had been 0.5 grains. “Geeze Louise!!”    

     GG:    Ripley’s “Believe It or Not”, right?    

     D:    I’m looking at them all and still don’t believe it.    

     GG:    Here are the data sheets and targets for the 300 Winchester’s 200- grainer.     

     Donny again looked at the targets and marveled at the results:     there was an eight-shot, 1-inch zipper; a six-shot group of about 2 inches that was virtually horizontal; and a six-shot group less than 0.5 inches, again pretty much round.    

     D:    Impressive. But those results are only one step in evolving a load. For each bullet, I assume that you selected the powder that gave the smallest round group as the one you used to develop the actual load. How did those loads turn out?    

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     GG:    I expected that question. Here are the final 200-yard targets for each.     

     Donny’s jaw went slack. Each target had a three-shot group less than 0.3 of an inch. At 200 yards. From a hunting rifle. Shot from a bipod off a bench. “I would be thrilled if I could do that at 100 yards,” thought Donny.     

     Donny fished a dime out of his pocket and placed it over each three-shot group, each time easily covering it completely. He knew Marine DIs used the dime test to assess shooting skill at 25 meters.    

     D:    Dayum!    

     Tricked-out brass?    

     GG:      Nope.    

     D:         Necks turned; primer pockets uniformed?    

     GG:     Nope.    

     What you are seeing are results with stock brass and the reloading procedures I will show you using the equipment and tools you have purchased. Wish I could tell you the specific hows and whys of those results based on physics other than the blanket notion of pulse and harmonics, but it’s way beyond me. I keep waiting for this load development approach to lie to me, but it hasn’t so far.    

     You can see the powder I selected on the proof-load group data sheets. Find that specific powder on the pressure and harmonics data sheets and note the powder charge for each bullet when I first got extractor groove expansion. Then look at the actual powder charge used for each of the 200 yd proof-load groups.    

     Donny studied the data sheets.     

     D:    The proof-load powder charge for the 200-grainer is ½ grain less, and the proof-load powder charge for the 240-grainer is 0.2 grain less. Looks like Ol’ Skip pointed you in the right direction,    

     GG:    He sure did. The skeptic in me has always wondered if I could get excellent accuracy without this Buck Rogers harmonics evaluation. Just select a power and run with it. At the end of the day, I don’t think so. Particular cases and particular

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powders go together like peas and carrots. With a particular case, one powder works extremely well with lighter bullets; another powder works extremely well with heavier bullets. I think the actual case dimensions and configuration affect the harmonics of the pulse.    

     D:    How does the maximum powder charge you identified for each bullet compare to the published values?    

     GG:    They don’t. Not even close. My 300 Winchester chamber has been throated to accommodate the 240-grainer, so the chamber’s volume is way more than an industry standard chamber. Which brings up a good point:     to be a truly successful hand loader, you need to believe that every rifle is an individual with specific likes and dislikes. As a hand loader, I would suggest you get into the habit of literally asking the rifle for a dispensation, then critically observe the response. As I have said before, the system or rifle always tells the truth. I can’t tell you how many times I have regretted callin’ mine lyin’ dogs. The rifle’s final response has always been “I told you so, smart a$$”.    

     D:    Did the targets I showed you give any indication that my system liked either powder that I used?    

     GG:    Yes.     

     Donny waited for GG’s customary explanation associated with either a yes or no. There was none forthcoming.     

     D:    And?    

     GG:    We shall see. What I think and what your system actually indicates can be way different. That’s why we are out here, to ask your system which powder it prefers, if any. It could barf on both. Let’s get started and find out.   

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