Bosslog

Tom Roster’s May/June 2026 Shooting Sportsman column, “Copper Shot: What It Is and Isn’t,” takes a hard position on copper shot. That’s fine. But if copper is going to be judged, it should be judged by the same rules that were used to make steel acceptable in the first place. This isn’t just about copper. It is about a ballistic framework that was built to justify steel under constraint and is now being applied inconsistently to modern materials.

Lead shot wasn’t banned nationwide for waterfowl until 1991, but the case for steel was being built long before that. As far back as the late 1970s, Roster was involved in steel-shot promotion and field evaluation tied to agency programs. The message was simple: steel could work if hunters changed the system around it. Anyone who made that transition understands the gap between how steel was promoted and how it actually performed in the field. That gap is what led me to start Boss. Our early customers felt the same way. They wanted something that brought back the kind of performance they remembered from lead. That’s why Boss Bismuth resonated immediately when we launched in 2018.

That context matters, because steel was never ballistically equal to lead. Steel runs roughly 7.6 to 7.8 g/cc. Lead is about 11.3 g/cc. Copper is 8.96 g/cc, and bismuth shot as commonly used is about 9.6 g/cc. Steel only worked because the system around it changed:

So let’s be clear. Steel was not equivalent. Steel was compensated. That is the standard that was accepted.

Reference (historical steel promotion context):  

In his column, Roster writes:

“From a density and lethality standpoint, ‘copper shot’ is going to be pretty close to steel shot.”
— Shooting Sportsman, May/June 2026

That’s a density argument, not a complete ballistic argument.

He also writes:

“CIC shot will need a fully two-sizes-larger pellet to compare ballistically to lead.”
— Shooting Sportsman, May/June 2026

That’s the steel-era model being applied to copper. But copper isn’t steel. It is denser than steel, softer than steel, but ductile and resistant to fracture in a way bismuth is not. That matters under setback, choke constriction, and high-velocity launch conditions. Steel gets evaluated as a system. Copper gets reduced to density. That’s not objective analysis.

The most important part of this discussion is velocity retention. Kinetic energy isn’t linear. It is velocity squared. Energy = grains × velocity² / 450,240. For #3 shot at .14":

At 800 fps retained velocity:

On density alone, copper looks only modestly better than steel. But if copper retains just 10% more velocity, the math changes fast:

That’s roughly 39% more energy per pellet. That’s the flaw in density-only analysis.

Material behavior during launch determines pellet shape and shape determines drag, velocity retention, and energy delivery.

Steel resists deformation and maintains spherical shape, which supports straight flight and patterning. Its limitation is density and faster energy loss. Bismuth and lead are denser, but they are prone to deformation and, in bismuth’s case, fracture. That creates irregular pellets, increases drag, and reduces total energy transfer.

Copper (CuProX™ with TurbuFlow™) sits in a different position. It is softer than steel, yet ductile and resistant to fracture unlike bismuth. It maintains more consistent geometry than deformed lead or fractured bismuth while carrying more mass than steel. CuProX™ with TurbuFlow™ is engineered to control deformation and manage airflow, reducing drag and improving velocity retention.

That difference is measurable.

As part of our development work on TurbuFlow™, including internal testing conducted in February 2026 in support of patent filings and discussed in greater detail on a Boss podcast, we ran controlled 40-yard gel testing using #3 shot at 1350 fps.

CuProX™ produced a mean penetration of approximately 4.32 inches with a standard deviation of 0.18 inches (CV ~4.2%). Under the same conditions, bismuth produced a mean of approximately 4.04 inches with a standard deviation of 0.51 inches (CV ~12.7%).

The average difference is meaningful. The consistency difference is decisive.

Bismuth showed nearly three times the variation in penetration, including low-end results that fall well below the group average. Those are not statistical noise. They represent pellets that failed to carry sufficient energy to the target.

CuProX™, by comparison, delivers energy in a tight, repeatable window.

Because performance is not defined by peak energy.

It is defined by how reliably that energy is delivered across the entire pattern.

Conditioned copper #3 shot at 60 yards produced:

Mean: ~3.65" | SD: ~0.20" | CV: ~5.5%

That low variation reflects consistent velocity and energy delivery across the pattern.

Boss internal comparative testing shows:

Copper at 60 yards ≈ steel at 40 yards. That’s roughly a 20-yard extension in effective penetration range. That’s not “pretty close.”

The confusion around “copper shot” isn’t really about performance. It is about identification in the field. The U.S. Fish and Wildlife Service already defines approved non-toxic shot types, and copper-based categories exist within that framework. The issue is verification. To address that, we developed the Boss MkIII shotshell tester to help differentiate shot types in a simple, repeatable way. At the request of USFWS, we have pursued third-party evaluation of the MkIII platform to ensure independent validation. This isn’t about changing regulations. It is about making them workable in the field. Once that clarity exists, the question isn’t classification. It is performance.

When we first started working with copper, the goal was simple. Get close to bismuth performance. After a year of applying physics beyond density alone, we reached a different conclusion. Copper doesn’t just match bismuth. It can exceed it. When copper is driven at velocities typically associated with steel, where bismuth can struggle due to pellet fracture under setback, that advantage becomes more apparent. That’s where the separation happens.

Copper’s combination of:

Allows it to operate in a performance window that bismuth can’t consistently reach.

Roster’s article treats copper like a static material. That’s the mistake. Steel was never judged that way. It was optimized into usefulness. Copper deserves the same standard. And when CuProX™ with TurbuFlow™ is evaluated as a complete system, not just a density number, it doesn’t behave like steel. It doesn’t stop at bismuth. It creates a new performance lane.

Copper is not “pretty close.” Copper is different. By design.