Book Chapter 28-Home

Hunting Bullet Metrics

Apply Terminal Performance Truth

AFRICA HUNTER QUEST©

Chapter 28 - THE PILGRIM’S SYSTEM SELECTS THE POWDER

Donny was grateful that the wind flag barely moved. Controlling the cant of the rifle was bad enough without having his off eye do double duty by monitoring wind conditions. He was holding and breaking his shots to the point he believed there were no fliers. However, there was no positive corroboration showing up on the target. The pattern that was showing up 100 yards away was beginning to form into what was roughly an equilateral triangle, with each side about 2 to 2½ inches long. The shots hop-scotched from triangle side to triangle side, with no shot in sequence really liking each other, except for the last two shots, 6 and 7.

Donny had carefully measured the extractor grooves after each shot. He had carried the brass and dial calipers over to the edge of the range roof to have good light. The first 6 showed no extractor groove expansion. The 7th, at 1½ grains beyond published maximum, had both its maximum and minimum diameters expand at least 0.00025 inches. There was no mistake.

GG hadn’t said a word during the entire sequence. It was unnerving. No encouragement. No spot corrections. Just nothing. Expressionless. “Is he having some private joke at my expense?” thought Donny. “Am I the gorilla with the greased football?”

D: All the shots except the last one was less than maximum pressure.

GG just nodded his head. It was infuriating.

D: What do you think?

GG: What do you think? Suppose I wasn’t here and you were literally on your own. How would you assess the results?

“I get it,” thought Donny. “The Old Man didn’t have anyone to ask. He had to decide for himself how to proceed, or whether to proceed at all. ‘I don’t know’ wouldn’t be an appropriate response because GG didn’t know either when he first attempted this. If I assume that what I have just done is fundamentally and conceptually sound, what truth is my rifle trying to tell me?”

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D: The whiz-bang 300 Winchester targets of your pressure and harmonics testing show multiple sequential impacts that like each other. The aggregate shape of the impacts formed a circular group. Mine don’t. My group is kindly shaped as a triangle. Except for the last two shots, none of the sequential impacts seemed to like each other. The fact that the last shot apparently exceeded maximum pressure means that its impact, no matter how potentially favorable, should be ignored.

Donny paused to collect his thoughts. What about how his rifle had shot when he was shooting the loads that he and his dad had ginned?

D: I had worked up a trial load at my dad’s with this powder that the rifle really didn’t like when I shot it the first time. Based on today’s results, I was potentially a full grain shy of where I needed to be in terms of powder charge to give a fair appraisal to his approach. Even so, the group I shot today doing mad science is obviously smaller than my previous one. I don’t think I can hang my hat on what I shot before today. Today’s result is the one I need to focus on.

GG nodded his head.

GG: So, what is your final assessment of today’s result with that powder?

D: Not knowing any better, I would say that my rifle just tolerated this powder. I suspect impact chaos with no identifiable pattern would have shown up on the target if the rifle had barfed on the powder. In the grand scheme of things, a 7-shot group of about 2½ inches could be considered by some as lower-bound reasonable for off-the-shelf hunting ammo if the target were the lungs at less than 100 yds.

GG smiled and nodded his head.

GG: Yep. The pursuit of excellence always needs a perspective grounded in reality.

D: Could this powder potentially give me the accuracy I want?

GG: Damned if I know. Solve no problem before its time. You haven’t tested the other powder. Fiddle with this one only if you believe you need to. It’s gonna be what it’s gonna be.

Donny nodded.

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D: Do I need to shoot a fouler with the slower powder?

GG: No. Another old wives’ tale as far as I’m concerned.

Donny shifted the rear rest slightly so that the rifle aligned on the second target with the array of small squares. He again dry fired on the center square, making sure his muscle memory hadn’t forgotten anything.

Donny selected the cartridge with the lowest powder charger of the slower powder and then began his sequence of firing, followed by measuring the extractor groove. His first shot impacted at least an inch above his aim point. He wondered if target chaos would now commence, because all of the impacts of the faster powder were below where the first shot of the slower powder had impacted. He measured the extractor groove and determined that it hadn’t expanded. Even so, Donny had become nervous and he couldn’t keep a Han Solo “I’ve got a bad feeling about this” from disrupting his concentration.

To calm himself down, Donny dry fired several times before loading the next cartridge with ½ grain more powder. He aimed, concentrated, and felt he broke a perfect shot: good sight picture, good hold, good breath control, good trigger squeeze, no wind.

He looked through his scope and audibly groaned. His second shot was at least 1 inch higher! He measured the extractor groove and determined that it hadn’t expanded. Nervous had now turned to agitated. He felt the test results thus far were a precursor to an epic disaster. The Old Man stood behind the uber binos, not saying a word, with no facial expression of good or bad. His whole persona was dispassionate indifference.

Donny once again forced himself to calm down by dry firing. Just as he squeezed his last dry fire practice, he felt a slight puff of wind on his face. “Fabulous,” thought Donny. “The Accuracy Gods now have decided to give me the flying fickle finger of fate.”

He instinctively raised his head so he could clearly observe what the wind was doing, or as he soon assessed, trying to do. The flag was gently fishtailing in response to the north wind trying to decide if it was time to blow. His rifle was pointed north, directly into the wind that was trying to establish itself. The fishtail oscillations of his wind flag became less pronounced, as the prevalent wind direction began to

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assert itself. “Just wait for a period of no oscillation and a dominant direction,” he thought.

Donny played same and different for a while and decided the prevalent direction was a tad more northwest than just north. He then resumed his position on the rifle and acquired his target. He held steady, waiting for the preferred wind direction. When he saw the flag orient a tad west of north, he squeezed off his shot. “Good one,” he told himself.

Donny looked into his scope. He couldn’t find the impact!!! Had he been buggered by the wind? He looked again. Still nothing. Not on the target. Not on the backer. Hell, not on any target! “$#!+,” he mumbled.

GG had been watching Donny’s reaction, grinning like a Cheshire cat. Donny was so befuddled he hadn’t turned around to ask where the impact actually was. The Pilgrim needed some relief.

GG: Cannibal impact. The second one ate it.

Donny turned around and looked at GG in disbelief.

D: Same hole as the second shot?

GG: Yep. And I’ll bet your pressure is okay.

Donny again looked through his scope, fixing his attention on where shots 2 and apparently 3 had impacted. The hole seemed a tad oval, oriented slightly vertical and obviously blacker than the hole made by his first shot.

D: What power is that contraption?

GG: Fifty.

D: Geeze Louise!

Donny then measured the extractor groove. No change. “How in blazes did the Geezer know that?!”

D: No change.

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GG: Compose yourself before you shoot the next one. Take your time with the wind. Shoot your condition.

Donny nodded and positioned himself on the rifle, this time focusing on dry firing only when his condition presented itself. When he was sufficiently calm, he chambered the 4th round in his powder sequence. When he finally broke the shot, he knew it was good.

When he looked through his scope, he focused on the impacts at 2 and 3. The area seemed blacker and now obviously more oval with vertical the preferred orientation.

D: Same spot? Another cannibal?

GG: I’m not gonna argue. Check the extractor groove.

Donny took about a minute to measure, as he suspected this one was really important.

D: Same.

GG: Take your time with the 5th. No excuses.

By then, Donny had a ritual established for prepping the shot. He followed it, then broke the shot. “Good one,” he thought.

Donny looked into the scope. “Damn,” he thought. “Way low and right, at least 1½ inches from the 3 that really like each other.”

GG: Measure the extractor groove. I’ll bet it has expanded.

Donny measured the extractor groove. Sure enough, both the maximum and minimum diameters had enlarged by at least 0.00025 inches. He really wasn’t surprised. The testing he had just completed had probably been replicated by the Old Man dozens of times.

D: Extractor groove has expanded.

GG: Yep. What do you think?

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D: Seeing is believing, but I still don’t believe it. First of all, I didn’t think it was possible, with all due respect to your targets. That is harsh and implies you lied to me, but that is how I felt. Regardless, I didn’t think my system was capable of that, let alone me being able to do it. Right now I am on sensory overload.

GG nodded and smiled faintly. He knew the Pilgrim had just experienced the equivalent of Roger Bannister breaking 4 minutes in the mile.

GG: Beyond that. Any assessments?

Donny sat and tried to collect his thoughts. It wasn’t easy. The slower powder was the obvious choice, but why?

Donny looked through his scope and pondered the pattern on the target. GG had never definitely said that the pattern was important, maybe even more important than the potential common points of impact in the pattern. Even with his limited data set, the first four shots had strong vertical. The impacts that indicated three that were kindly in the same hole were slightly oval with a vertical orientation, potentially contributing to the vertical ‘sameness’. Flimsy, because that assessment relied on no aiming error, regardless of ‘aim small, hit small’. Yet there all three of them sat in a group hug. He would table that pattern observation pending a discussion with GG.

His last shot, the one that had a powder charge that produced pressure beyond maximum, was an obvious kicker. His hold had been good. Wind was not possible as an explanation for its dramatic drop from ‘we three’. “Harmonics change,” thought Donny. GG’s correct extractor groove prediction indicated that this type of flier was common. Could this kicker be an indicator of stellar accuracy as implied by the previous three shots?

The reality of the ‘we three’ was compelling. Cosmic intervention was always a possibility, but really? GG had said that the rifle always told the truth. Was it telling the truth? What occurred on the target appeared to be confirming Skip Talbot’s axiom. What had GG said? His loads were at or slightly less than maximum pressure?

D: It’s hard to look at a gift horse and not be suspicious. But between the two powders, the system indicated it could potentially like the slower powder and merely tolerated the faster one. I have no basis for comparison, so I have to accept that three shots pretty much into one hole is at least a potential indicator of excellent accuracy. Not only that, the three shots that like each other are shy of maximum pressure, a

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condition you seem to seek out with your load development. It could all be a shed filled with horse manure, but that doesn’t eliminate the possibility that there might be a horse in there somewhere.

GG nodded his head.

GG: Well done. It’s hard to believe that the odds are good when the goods are odd. Regardless of the hows or whys, it’s tough to argue with the results of that three-shot sequence. I assess you have been potentially smiled upon by the Accuracy Gods, particularly since you only have two powder choices. Let’s shoot the five you have loaded to ½ grain below published maximum, the same powder charge as your shot number 3. The group pattern will tell me where we stand with that powder choice and where this load potentially needs to go, including the dumpster.

Donny repositioned the ammo box for ready access to the group proof rounds. His recent wind evaluation indicated there was a prevalent condition in which several shots in relatively rapid succession could be made before the condition changed.

GG: Adjust your scope so your zero is closer to the impact of the three amigos. You really don’t want a precise zero to risk shooting out your actual aim point. You’re simply trying to reduce potential for one of the shots not hitting the target, then wondering where in blazes it went.

Donny did hand grenades with the elevation turret and left the windage turret alone. He then positioned himself around the rifle and practiced with dry fires according to his ritual. When he was ready, he fired his five proof rounds at a different aiming square, none of which he called a flier.

The group pattern resembled a near-vertical zipper like the one he had previously shot. The big difference was the one today was way smaller, less than half the length of the previous one. Donny estimated its length was about 1½ to 2 inches or so. Although none of the shots were cannibals, he found it curious that all of them came close to actually touching each other. He had never seen anything like it, and he certainly didn’t know if the result was good, bad, or ho-hum.

GG: You are living right, Pilgrim. You should be able to easily fix that.

D: How do you know that?

GG: From the target pattern. Adjusting either the powder charge at 0.1-grain increments or the seating depth at 0.001-inch increments from the baseline readings that produced that target group will change it, either favorably or unfavorably. For the hunter or casual shooter, those adjustment tools are really all that are needed to achieve better accuracy.

D: The pattern today is the same as when I shot the one with the thrown powder charges and bullets seated based on cartridge overall length, only it’s way smaller. Are you saying powder charge and seating depth are responsible?

GG: More than likely. What I do know is that the rounds you shot today in your proof group all had consistent powder charges and seating depths reference to the bullet’s ogive. Lord knows what they were with the other ones. Apparently, they were close enough to the ones you shot today to produce the same general group pattern.

D: But the short-range benchresters throw their powder and don’t check seating depths. How come they shoot such tiny groups?

GG: First of all, the PPC case is a premeditated design that I think results in harmonic magic. You saw the harmonic magic with the three amigos with a powder difference of 1 grain. Some cases just shoot; the PPC case shoots lights out. Second, the bullets they shoot are more consistent than the ones mere mortals shoot at game. I won’t go into what I mean by consistent, but it goes far beyond ogive to tip uniformity. Third, these bullets are seated waaaaay into the lands, and such a seating depth is totally inappropriate for hunting ammo. Lastly, what you are referencing is original ‘needed to’ procedure that has morphed into chanted religion.

When the PPC case design first came out, it was a real pain to prep them. The shooters made do with a limited number of cases that they pretty much had to reload each time at the match to shoot the next target relay. Powder could not be electronically measured back then, so they used precision machined powder measures to throw their powder charges rather than weigh them. The powders they typically used got squirrely with temperature changes, so they really couldn’t pre-weigh a batch and take it to the match. Hence, the competitors had to ‘throw as you go’.

D: Sir, please don’t misinterpret what I’m about to ask you. Your 300 Winchester targets are all the proof I need to know that adjusting powder charges

and seating depths by those tiny increments can give exceptional results. How come that isn’t common knowledge?

GG: Don’t know for sure. I suspect it’s fear-based. Each shooting discipline is tribal, with each believing that what any other discipline does is irrelevant, inapplicable, or both. Innovation or adjustments to their standard practice based on what comes from outside the tribe is not encouraged because it upsets all manner of pecking order and status quo. Folks are just scared or intimidated to even try. Fear of failure. Fear of ridicule. You have the courage to try, coupled with the persistence and mental acuity to critically evaluate the results.

Donny blinked in surprise. An actual compliment. Sincere. Not the patronizing, superficial PC crap typically dispensed.

D: Thank you. I appreciate your pointing out the path and the guideposts. What do I need to do to close the zipper?

GG: There are three primary group patterns of interest: vertical, horizontal, and cloverleaf. You need at least three shots to identify them; more are better. I have arbitrarily decided that a circular group is a cloverleaf in disguise.

You need to recognize that these patterns are very general. You have a near-perfect vertical group down there. Individual shot impacts could have wiggled from side to side in an effort to obscure the obvious vertical component. That’s why more shots are better so you have a stronger sense of the shape you are trying to adjust.

Load development is trial and error in search of favorable system harmonics. Start first by either holding the powder charge constant and adjusting the seating depth, or holding the seating depth constant and adjusting the powder charge. Never change both at once.

Adding or deleting powder demonstrably changes both the system pressure and harmonics. Changing the seating depth primarily changes the harmonics with what I believe is a modest effect on pressure. As long as you don’t exceed maximum pressure, there are multiple combinations that work, with typically only one that can be considered ‘the best’. As I have said, where I have found ‘the best’ is within spittin’ distance of about ½ to a couple of tenths of where the extractor groove first starts to expand. That being said, your system has the final say of what it considers ‘the best’. All I’m saying is that Skip’s advice is a good place to start.

Both vertical and cloverleaf size can be typically reduced with powder increases, seating depths extended toward or further into the lands, or both. If you increase powder and/or seating depth too far, you can string horizontal or the group seems to blow up into what I call a chaos group.

D: Horizontal? You can get a horizontal group with no wind?

GG: Yep. I’ve had zippers rotated. That’s why paying attention to the wind is so important. You may miss your rifle telling you that you have gone too far with the powder or seating depth and need to back up.

D: So, with the group I just shot, an initial strategy could be to keep the same seating depth, and do three-shot groups at 0.1-grain increased powder increments?

GG: Bingo. With a hunting application, it’s best to stay out of the lands, if possible, or no more than about 0.008 inches into the lands. If you can’t, between 10 to 30 thousandths off the lands is a good place to look. I’ve gotten excellent results as far as 0.207 inches off the lands. That’s pushing ¼ inch. There is no minimum or maximum. Just make sure you maintain the same distance off the lands. I have found you need to compensate for throat erosion. If you use seating depths that are into the lands, use dummy rounds with no powder or primer to make sure you have enough neck tension to both hold the seating depth and extract a bolted round without pulling the bullet out of the case.

Remember that today is at least the second firing of the brass and it really needs to be annealed before resizing it again.

D: So, let’s assume that my three-shot group starts to close down the vertical with increasing powder at 0.1-grain increments, but blows up at 0.3 grains more. Would a new strategy be to start with a powder charge 0.2 grains greater and increase seating depth into the lands at a 0.001-inch increment up to 0.008 inches as long as a dummy round proved the bullet retained its seating depth and was not removed upon extraction?

GG: That would probably be okay, although I would set up the dummy round at 0.012 inches into the lands to make sure. Also make sure a bullet seated that far into the lands fits the magazine.

D: I suspect that there is way more to this than the simple back-and-forth strategy between powder and seating depth that you have described. Can I show you targets and ask for your advice if I get stumped?

GG: Sure. Make sure you bring the data sheets with you. Speaking of data sheets, go down and retrieve the targets. You need to make sure the paper work is knitted up before you leave the range.

Donny went down and collected the targets. When he got back to the benches, he numbered the impacts on the targets and referenced them to the load on the data summary sheet. Donny held out his hand when he was finished.

D: Thank you, sir. This morning has been a real eye opener. I appreciate what you have shown me. I understand why you show up at the range when you do. The concentration needed can be intense. Booting a shot from a lack of focus could have gotten me pursuing a bogus strategy.

GG: You are welcome. All part of the snappy service. Good luck.