AFRICA HUNTER QUEST© 

Chapter 16 - THE DUAL-LEAD CELL BULLET 

    D:      Battery bullet? 

   GG:   A bullet with two distinct copper alloy-enclosed lead cells. This design is the granddaddy of all generic designs that evolved beyond the simple cup and core; the first premium bullet. 

    There is a front nose cell of lead alloy, separated from a rear ‘trunk’ cell composed of either lead alloy or lead by a barrier wall of copper alloy. A copper alloy jacket encases both the nose and trunk lead cells. Depending on the manufacturer, the front nose cell of lead alloy can be either bonded or unbonded to the copper alloy jacket. The rear trunk cell, housed within the shank portion of the bullet, can either be lead or lead alloy that is typically unbonded to the surrounding jacket. The intent of the enclosed rear cell is to preserve some design percentage of mass that will be unaffected by the impact stress the front cell must endure. Thus, there is no jacket-core separation, an issue that this design may have originally intended to rectify. The encased rear trunk cell also serves what I believe is the political objective of reducing the amount of mass lost during impact and penetration. As I have repeatedly said, I believe there can be demonstrable benefit to wound cavity production and enhanced bleed-out potential from shrapnel being flung from the bullet along its penetration path. 

    The generic design affords the flexibility to further tune the bullet’s performance beyond that of the cup and core and bonded-lead cell generic designs. Location and thickness of the copper alloy barrier can be varied to adjust the rigidity of the jacket walls in the nose cell area.  The rigidity of the nose cell jacket can also be adjusted by changing the jacket’s taper and thickness. This tapering and the thickness can be compatible with scoring the tip’s jacket wall interior at 90 degrees. The lead metallurgy can be varied to adjust its deformation characteristics. All of these design features can be integrated in an attempt to control the rate at which the mushroom forms, its maximum diameter, and its symmetry.  

    Depending on the manufacturer, the nose cell lead can be bonded to the jacket. As we have discussed with the bonded-lead core bullet, that bonding better controls and slows the rate at which the mushroom deformation occurs. A beefed-up jacket in the nose, integrated into the copper alloy wall that separates the cells, is better

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able to limit the maximum extent to which the bullet can expand. Both of these design features likely tend to enhance the penetration potential of this genetic design. 

    The bullets that have unbonded lead in the front cell act more like an improved cup and core bullet. Compared to a cup and core bullet, the increased jacket taper and thickness in the nose cell area can reduce the rate at which the mushroom forms. Any reduced rate of mushroom formation likely enhances this generic design’s ability to penetrate beyond that of a typical cup and core bullet of the same weight. That being said, the rate of expansion is uncontrolled and likely faster than with a bonded-front lead cell. As with the cup and core bullets, the design with unbonded lead in its nose cell can shed a significant volume of lead at high impact velocities. 

   The original generic, dual-lead cell bullet was introduced in 1948. I believe that its introduction was in response to the intense muzzle velocity race that had just begun. The manufacture of this original bullet continues to this day. I think this original design’s longevity is testimony to its toughness, flexibility and demonstrated field performance. 

    The dual-lead cell bullet I tested had a bonded-lead nose cell. The bullet is a 30-caliber, 180-grain, flat-base spitzer. Like the 200-grainer, the copper alloy jacket extends all the way to the bullet’s tip. There is no exposed lead in the bullet’s profile. This 180-grainer had an obviously bigger diameter tip than the 200-grainer. Based on the four-petal mushroom I observed in the recovered bullet, it also had the interior of the nose cell jacket scored at 90 degrees. This implies both a comparatively thick jacket sidewall and a stout jacket taper.  

   Fired from my 300 Winchester, its impact velocity was also 2570 fps, the same as the bonded-lead core 200-grainer. It penetrated 27½ inches, had a retained weight of 99%, a percent deformation of 45%, and an expansion ratio of 1.93. The recovered bullet had an almost perfectly round mushroom. There was no indication that the bullet had tumbled. The wound cavity looked like a somewhat anemic guppy. 

    Based on my conversations with multiple PHs, both the original unbonded nose cell and more-current bonded nose cell generic designs are highly regarded in South Africa. The original design with the unbonded front lead cell was pretty much considered the gold standard for trophy hunting plains game up until about 15 years ago. Newer generic designs were then being commonly used, and these designs retained more weight. I believe the conclusion, spoken or otherwise, was that the higher weight retention of these newer design bullets made them ‘better’ regardless of past demonstrated terminal performance. I speculate that what had worked exceedingly well for literally decades was now considered by some to be marginal to unacceptable simply based on weight retention, regardless

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of the chamberings and attendant impact velocities. 

    D:      (Smirking) Sticks in your craw, doesn’t it, because it is an indirect putdown of both tried-and-true and cup and core bullets. 

    GG:   Not really. If actual field performance was marginal to unacceptable, then I think primary issues of penetration, wound cavity formation, time to death, or whatever other terminal performance measuring stick folks want to use should be the basis for that judgement. I think the preferred judgement approach is to first state what happened with the animal, next state why that terminal performance was unacceptable, and then relate the whys of poor performance to impact velocity and limitations in the generic design. There may be very legitimate reasons why there was a problem related to this specific design. But what I suspect happened was that any legitimate terminal performance limitations were obscured or even subjugated in deference to style points associated with weight loss. 

    D:      (Again smirking) So why didn’t you test the granddaddy of all the premium bullets? I would have thought that would be a must-do test. 

    GG:   I was trying to identify a 30-caliber bullet that I could use in my 300 Winchester that would pass muster as both a trophy bullet and a cull or meat-hunting bullet for rear quartering shots less than 300 yards. That meant I had to find a bullet that surpassed the penetration of the 200-grain bonded-lead core bullet, but also gave excellent wound cavity volume. I slothed out and picked a 180-grain dual-lead cell bullet with a front nose cell bonded to the jacket that has an established, decades-long reputation for both penetration and demonstrated terminal performance excellence on Africa plains game. The testing was an applied expedient rather that for pure research. 

    D:      If penetration was a concern, why not just use a solid copper bullet? 

    GG was annoyed. That was nothing more than another harassment question in a long line of harassment questions. “I suppose the Pilgrim thinks I am harassing him with mine and wants some payback,” thought GG. “I guess that’s the price I have to pay just to make sure the little $#!+ has gotten the key concepts.” 

    GG:   You tell me. 

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   D:      I suppose you had already completed testing on the solid copper bullets and had determined that the wound cavity volume would likely be anemic.  

    GG:   Yep.  

    D:      Why a 180-grainer instead of a 200 or 220-grainer? 

    GG:   Am I that obvious? 

    D:      Like an NRA life member at a MAGA rally.  

   GG:   I wanted to test at least a 200-grainer in that design to compare it to the 200-grain bonded-lead core bullet that I had previously tested. The manufacturer of the 180-grainer test bullet makes a 200-grainer, but not a 220. The 200-grainer was unavailable, but the manufacturer had off-the-shelf 300 Winchester ammo loaded with its 180-grainer in stock. I figured the 180-grainer would conceptually perform similarly to the 200-grainer, so I gave the 180-grainer a go.  

    D:      And? 

    GG:   In the contest, it finished sixth overall. Among the 30-calibers, it finished third in a field of five, behind the 200-grain bonded lead core and the tipped 240 match bullets. It beat out a 220-grain round-nose cup and core and the 165-grain solid copper bullet.  

    Its obvious terminal performance strength was its penetration. With a total penetration of 27½ inches, it placed fifth behind the three solid copper bullets and the 35-caliber, 250-grain cup and core. Among the five 30-calibers tested, only the 165-grain solid copper bullet beat its penetration with 34¾ inches. 

    Conceptually, its penetration performance made sense. A comparatively thick jacket with a beefy taper in the nose coupled with bonding to the alloy nose-cell lead likely reduced the expansion rate of the mushroom. As I have previously discussed, limiting the rate at which a mushroom is allowed to expand enhances its penetration potential. Furthermore, inspection of the recovered bullet revealed the presence of internal jacket scoring at 90 degrees that contributed to an almost perfectly round mushroom. This design feature contributed to a bullet that plowed straight, with no tumbling to retard penetration. Depending on impact velocity, I would expect the

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measured diameter of the mushroom could likely be the maximum that occurred during penetration. 

    I did no testing of a dual-lead cell bullet with an unbonded tip. Published pictures of this generic bullet indicate considerable deformation/degradation of the nose cell area can occur, particularly at high impact velocities. Even with this deformation/degradation, I expect this generic bullet would penetrate better than a traditional cup and core bullet because the likely thicker copper in the nose cell area somewhat retards the rate of mushroom expansion. The location of the copper alloy barrier between the cells limits the bullet’s longitudinal deformation, and thus contributes to enhanced penetration potential compared to a cup and core generic design. As with the cup and core bullets, the measured mushroom diameter of a dual- lead cell bullet with an unbonded front cell would likely not be the maximum diameter achieved during penetration. 

    D:      What about the 180-grainer’s wound cavity volume?  

   GG:   It was somewhat anemic compared to all the competitors, as it finished ninth in total wound cavity volume. Within the 30-caliber group, it finished fourth, besting only the 165-grain solid copper bullet. Although it only beat the 165-grainer in that category, its wound cavity volume was 43% greater, a considerable increase.  

    I think there are two reasons for the 43% difference in wound cavity volume of the 180-grainer compared to the 30-cal 165-grain solid copper bullet. Although the inferred rate of mushroom expansion of the 180-grainer was relatively slow compared to the cup and core and bonded-lead core bullets tested, it was likely way faster than the rate of the 165-grainer, solid copper bullet. Not only did it likely open quicker, but its expansion ratio was 1.93 compared to 1.69 of the 165-grainer. 

    D:      You said the impact velocity of the 180-grainer was 2570 fps. That’s the same impact velocity of the 200-grainer. Why so low? I would have thought it would be at least 100 fps faster. 

    GG:   Conservatively loaded. The manufacturer claims a muzzle velocity of 2919 fps out of a 24-inch barrel. Mine is a 22 incher. If you deduct about 30 fps per inch from the muzzle velocity due to my shorter barrel and run the ballistic numbers based on the manufacturer’s published BC, the impact velocity at 135 yds is pretty much dead nuts to what I got. Tip of the cap to the manufacturer for being truthful about its product’s muzzle velocity and the BC. Not very common. 

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    D:      Thoughts on the range of operational impact velocity? 

   GG:   Big time speculation, as there are no manufacturer recommendations for the design with either the unbonded-nose cell or bonded-nose cell. There are only pictures of deformed bullets at velocities that I infer are meant to be impact velocities. For the design with the unbonded lead in the nose cell, I would personally want impact velocities on the shoulder between about 1900 to 2900 fps. For shoulder shots using the bonded-lead cell nose, I would want impact velocities between 2300 to 3000 fps. These impact velocity ranges can be considered nothing more than a scientific wild-a$$ guess. 

    D:      Those velocity ranges are surprising. You have given the unbonded- nose cell a greater range of impact velocities, but have only given the bonded-nose cell an extra 100 fps on the top end. What gives? 

    GG:   Based on the manufacturer’s picture of the one with the bonded-nose cell, both the bullet’s deformed length and mushroom diameter increase with increasing impact velocity. These increased deformations tend to limit a bullet’s ability to penetrate. There is a picture of this exact 180-grain bullet that has been subjected to an impact velocity of 3325 fps. It’s just a button-shaped nub. All these pictures indicate to me there could be a serious reduction in penetration at elevated impact velocities. Hell, 3000 fps for a top end may be generous.  

    These pictures also tend to corroborate my earlier assessment that the measured mushroom diameter of dual-lead cell bullets with a bonded-nose cell may be the maximum or close to the maximum that occurred during penetration. That inference is also substantiated by the 1% weight loss of the 180-grain test bullet. 

    As far as the bottom end goes, the bonded-lead front cell design has it performing like a bonded-lead cell bullet. Foster has given those a lower bound of 2400 fps for producing emphatic kills, so I considered dropping the lower bound to 2300 fps as generous. 

   As for the unbonded-nose cell impact velocity range, the generic design allows for an aggressive and beefy taper for the front cell’s jacked compared to what typically occurs on a common cup and core bullet. That allows somewhat slower mushroom formation than would likely occur with a cup and core bullet. That being said, I wouldn’t want to get too freaky with the unbonded-nose cell design on the top-end impact velocity with the attendant risk of potentially stripping away the entire nose cell before it could get to the boiler room. The presumed stiffening of the

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jacket surrounding the nose cell lead also is why I increased the lower bound impact velocity up to 1900 fps instead of 1800 fps that is typically assumed to a cup and core bullet. 

    D:      (Smirking) Damn, you are careful.  

    GG:   I try, but there is always the possibility I may not be careful enough. In hunting, there are no Mulligans. 

    Besides being wild-a$$ guesses, those impact velocity ranges are likely not sweet-spots where an increase in impact velocity results in an increase of both penetration and wound cavity volume. As with all generic bullet designs, actual gel test data that include wound cavity volume are needed to strategically assess likely bullet terminal performance.  

    What are your takeaways concerning dual-lead cell bullets? 

   D:      You didn’t do any testing on an unbonded-nose cell generic design. You are of the opinion that the reason this bullet is no longer the fair-haired child of Africa plains game hunting is because recovered bullets have appreciable weight loss compared to more evolved generic designs. I would expect that if you had done any testing with your 300 Winchester, you would have found that to be basically true. You continue to maintain that weight loss is an investment in wound cavity volume. I would also expect that your testing results would have contributed testimony to that. 

    The design kindly has a fail-safe penetration feature with the enclosed rear cell. My final expectation would therefore be that a 30-caliber dual-lead cell bullet with an unbonded front cell launched from your 300 Winchester would not embarrass itself in your competition, likely exhibiting balanced wound cavity formation and penetration. 

    That being said, the nose cell is still relatively fragile. Its performance may not contribute to achieving penetration compatible with a rear quartering shot. At the end of the day, this design would likely be a very good trophy bullet, but field experience would be necessary for it to be considered acceptable for a rear quartering shot.  

    The dual-lead cell bullet with a bonded-nose cell that you tested is very different. The nose cell design facilitates penetration, but apparently not to the point

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where wound cavity volume is only given lip service. Its penetration exceeded your arbitrary limit of 24 inches, which likely qualifies it for all shot angles.  

    I cheated and read Robertson’s chapter on hunting kudu. He said rear quartering shots were common. Other than the 165-grain solid copper bullet, the 180-grainer is the only 30-caliber bullet that would qualify for a rear quartering shot if the impact velocities fell within the ranges you believe are reasonable for this generic bullet. At the end of the day, this 180-grainer appears to favor penetration over wound cavity volume, but not to an unreasonable degree.  

    GG was impressed. For anyone to knit up performance assessments like the Pilgrim had, literally without seeing numbers, was outstanding, snarky attitude notwithstanding.  

    GG:   Brilliant! Absolutely brilliant. You knitted that up better than I could do. You are beginning to master bullet performance concepts and apply them in the abstract. You are almost practicing engineering without a license.  

    D:      Maybe so. But what interests me is there is only one more generic bullet to learn. Are you saving the toughest for last? I hope not. I’ve got things to do at the farm. 

    GG:   I think understanding what goes on with the final generic design will be a snap for you based on what I just heard. It combines design features we have already discussed into what may evolve into an uber bullet generic design.  

    D:      (Smirking) You’re gonna wonk out, aren’t you? 

    GG:   (Grinning like a Cheshire cat) Been known to occur.

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