Book Chapter 17-Home

Hunting Bullet Metrics

Apply Terminal Performance Truth

Table of Contents

AFRICA HUNTER QUEST©

Chapter 17 - THE SINGLE-LEAD CELL BULLET

D: (Smirking) So what generic bullet design has pegged your terd meter?

“Smart a$$,” thought GG.

GG: Terd meter?

D: (Smirking) Techno-nerd meter.

GG: Oh. (With a Herculean effort to keep a neutral facial expression) I call it the single-lead cell.

D: Single-lead cell? Aren’t cup and core and bonded-lead core bullets single-lead cell?

GG: Technically, yes. But in the case of this bullet’s generic design, the lead volume and weight are small compared to the material that surrounds it. The lead cell is either in the nose or in the shank, and the material surrounding it is copper.

D: Copper? Just like the solid copper bullets we discussed?

GG: Yep. I think the design with the lead cell in the shank is the easiest to explain, so I’ll start with that one.

I believe the reason for the lead cell in the shank is simply to reduce the bullet length to a more manageable level to preserve case and chamber volume. When that happens, seating depths are shorter and muzzle velocity can be improved to the point where it approaches that of a comparable weight bullet comprised mostly of lead.

Let me state from the git-go that I have done no testing on any bullet of this generic design. So from now on anything I have to say is nothing more than speculation. That being said, the testing I have done on the other generic bullet designs has given me strong clues about what to expect if I did test them, just like with the dual-lead cell bullet with the unbonded front cell. Again, hard data from manufacturers including wound cavity volumes and penetrations at selected impact velocities are not furnished but would be very beneficial.

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I expect the single cell design with the lead cell in the shank would perform pretty much like a solid copper bullet, with the preferred performance strongly focused on penetration. Just as with the solid copper bullet, I would not expect it to produce significant wound cavity volume.

In my opinion, the single cell design with the lead cell in the tip has the best potential of all the designs to be actually tuned to produce any combination of penetration and wound cavity volume that a designer wanted. The key is the tip design and how the mushroom is controlled.

D: Rate of expansion, symmetry, and final diameter?

GG was impressed. The youngun was indeed a sponge and not a block of impenetrable granite, snark notwithstanding.

GG: Outstanding! The solid copper is way stronger than copper alloy. The actual cavity shape that forms the cell and its dimensions can be consistently controlled in the manufacturing process. Wall taper and thickness of the copper forming the cavity can be designed to limit the mushroom’s final diameter. The wall taper and thickness design will also help control the rate of mushroom expansion. Other design and manufacturing steps to control the rate of expansion are bonding the lead core to the copper, tinkering with the metallurgy of the lead, and adjusting the annealing of the copper in the tip. The relatively small front cell dimensions will limit the total length-wise deformation of the bullet, thus enhancing its penetration potential. Limiting the maximum mushroom diameter also enhances its penetration potential.

The copper jacket would likely be thick enough to allow internal scoring of the cell walls at 90 degrees to produce a symmetric mushroom. As with the solid copper bullets and the dual-lead cell bullet with the bonded-lead front cell, the scoring promotes straight plowing and reduces the potential for tumbling. Because the majority of bullet weight is copper, the bullet would have a long shank that can serve as a counter balance and backhanded rudder to better resist potential tipping forces.

D: (Smirking) If you were in charge of this bullet’s design, you would wonk out, wouldn’t you?

GG: Yes, sir!

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D: It’s obvious to me that you want to max out wound cavity volume with no real penetration penalty. If this generic bullet has the potential to produce this performance, why didn’t you test one?

GG: Because there are only two manufacturers of this generic bullet that I believe have a premeditated design intent to produce a bullet with truly balanced performance between wound cavity volume and penetration. The first was in the U.S. I say ‘was’ because it has since been bought out by a firm overseas. On an old website, it actually gave recommendations for both maximum and minimum impact velocities. As you can imagine, that got my attention and blood pumpin’. It is the only manufacturer that has stated that controlling mushroom diameter is a key design feature in controlling the actual penetration. If I could have gotten enough 30-caliber bullets from this manufacturer to work up a load, I’d have tested them in a heartbeat. Right now, the company is in limbo.

D: What about the second manufacturer?

GG: Same issue. Can’t get any bullets.

D: Why?

GG: The manufacturer is in South Africa. No U.S. importers that I know of.

Robertson talks about this company’s bullet performance in his book. What caught my eye was his reference to the obviously large wound cavity these bullets produced on game. Nothing abstract or theoretical, actual field performance.

I was fortunate enough to develop email rapport with the owner of the company. He is a dedicated hunter of my vintage. It is a bullet of his own design and a labor of love. He indicated he buys newsprint by the truck load for testing his bullets. I never asked what the objective of his testing was, as it could be easily interpreted as blatant industrial espionage by an Ugly American he didn’t know from Adam’s house cat.

But the conceptual principles associated with what is going on with the mushroom’s formation and limiting its maximum extent indicate penetration testing into dry newspaper, coupled with his ability to relate mushroom size obtained from this testing to the wound cavities he personally sees in the autopsies he performs, likely allows him to tune the tip to his personal satisfaction. That tuning would likely

include adjusting the tip configuration to get the balance between penetration and wound cavity volume that he wants based on his field experience.

I take great comfort in the inference that a South African practitioner, immersed in personally hunting African animals, is tinkering with a bullet design that is fully capable of both outstanding penetration and wound cavity volume. If he doesn’t know what is going on with actual bullet terminal performance in the animal and methods of tuning his bullet accordingly, no one does.

D: Any weight loss issues with this nose cone cell?

GG: I see you are having trouble letting that sidebar go. In a word, no. The bullet from this South African manufacturer has the lead bonded to the copper. That reduces the amount of lead lost as shrapnel. There really isn’t much lead either. The net result is that whatever lead is lost is likely minor. Furthermore, limiting the maximum mushroom diameter by using the structural rigidity of the jacket that comprises the cell likely affords this generic design the potential to have increasing penetration with increasing impact velocity regardless of weight retained.

D: (Smirking and loaded with snark) Since you did no testing, have you cast the other bullets of this generic design that are readily available into the pit of no redemption?

GG: (Again doing his best to deflect the insolence) No. For me, this is the generic design that absolutely screams for the manufacturers to furnish hard gel test data with wound cavity volumes, not pictures of deformed bullets or slo-mo video. Without these test data, I would be hesitant to select one for an actual hunting application without benefit of my own gel testing. Some of these front-cell bullets could potentially produce the same performance as a solid copper bullet, performance I am not naturally inclined to apply in any of my hunting scenarios, Africa or otherwise.

D: So you want a bullet with performance balanced between penetration and wound cavity volume?

GG: No comment. This isn’t about what I want nor what I would do or am doing. This is about you and some hard decisions you need to make concerning the potential for success of your current 130-grain cup and core in the Africa hunting scenario you have yet to define. Not only that, you have got to decide if you want your bullet performance to fall on the penetration side of the hall, the wound cavity

volume side of the hall, or somewhere in the hall with a balance between the two. With that in mind, what are your takeaways concerning this generic bullet design?

D: If I could find the right bullet with the right weight, this design could potentially offer a desirable combination of penetration and wound cavity volume. But because the generic design is capable of producing such a broad spectrum of terminal performance, lack of specific manufacturer-furnished test data that includes wound cavity volume means I would have to do my own testing to determine if a particular bullet gave the performance I wanted.

GG: Succinct and accurate appraisal.

D: Does that button up the five generic bullet designs?

GG: Yes, but not if you have questions I can answer.

D: What bullets have you selected for Africa use?