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The Ultimate Reloading Manual
Wolfe Publishing Group
  • alliant reloading data
  • reloading brass
  • shotshell reloading
The Ultimate Reloading Manual
load development

.243 Winchester and Copper Bullets Shooting Mono-Copper Bullets in the .243 Winchester

Author: Patrick Meitin
Date: Jan 12 2023

The test rifle was a Hardy Rifle Hybrid available from Legacy Sports International.
The rifle is super lightweight thanks to the carbon and a 7075 aluminum-alloy action.

My first big-game experiences involved a .243 Winchester and cup-and-core lead bullets. Because it was the only centerfire rifle I owned, I used that rifle – and those lead-core bullets – to shoot everything from coyotes to bull elk.

That was 40-plus years ago.

Obviously, much has changed in the intervening decades regarding bullet construction and powder technology. One of the largest developments is the monolithic copper bullet. Randy Brooks, who purchased Barnes Bullets from its original owner, Fred Barnes, is credited with bringing the idea to fruition. The Barnes X Bullet hit the market in 1989 to mixed reviews. Early X Bullets were noted for producing high chamber pressures, introducing copper-fouling and frequently failing to expand adequately on lighter big game.

The Hardy Rifle includes a 7075-grade aluminum-alloy action,
and a five-lug system seating into a high-grade steel base
found at the receiver end of the carbon-wrap barrel.

Barnes quickly corrected these issues, the Triple Shock bullet introduced “pressure-relief grooves” on the bearing surface, reducing pressure and fouling, and a modified hollowpoint cavity that initiated more reliable expansion. Polymer tips were later added, which seemed to promote even more reliable expansion. Barnes Bullets have become a favorite amongst serious big-game hunters, with a plethora of mono-copper bullets quickly following, including Hornady’s GMX (now the refined CX), Cutting Edge Bullets, Hammer Bullets, Quality Cartridge Game-StopR, and Badlands Precision, just as examples.  

This was inevitable. Copper is considered nontoxic (though it will kill trees). California started the trend with dubious no-lead “Condor Zones,” and eventually expanded to include the entire state. Some state and federal refuge lands followed suit. The fear of ingesting lead fragments steered still more hunters to copper bullets.

Love them or hate them, there are real advantages to the monolithic copper design – and some real disadvantages. The real con is copper is much lighter than lead, meaning a bullet weighing the same as a traditional lead-core slug, or even lighter, can require faster rifling twist for proper stabilization. Adequate rifling is just not available in many classic rifles, raising compatibility issues. Yet, that same long-for-weight dynamic can introduce excellent ballistic coefficients, granted enough rifling twist is available for stabilization. Pure or gilded copper is also consistent in makeup, and since copper bullets are milled instead of molded or stamped, they generally provide excellent consistency.

The largest selling point of monolithic designs is a high percentage of weight retention, which translates into reliability and deep penetration from a smaller, lower-weight bullet. I’ve seen figures, educated guesses I would call them, that say that adding 15 to 20 grains to the weight of a mono-copper bullet gives a shooter an idea of how it will compare to a lead-core slug’s terminal performance. For example, an 80-grain Barnes TSX BT would provide terminal performance comparable to a 100-grain Remington Core-Lokt. There is no empirical evidence this is true, but antidotal field evidence tells me it is. Given this stipulation, big-game hunters get flatter trajectory via lighter bullets that hit as hard and drive as deep as heavier lead slugs.

This makes the .243 Winchester a prime candidate for the copper-bullet treatment, turning a cartridge so many deem big-game marginal into a more lethal package. An 80-grain Barnes TTSX BT, for instance, becomes mule deer or caribou ready, a 90-grain Hornady CX suited to, say, elk duties with carefully placed shots.  

The Hardy Rifle includes a 7075-grade aluminum-alloy action,
and a five-lug system seating into a high-grade steel base
found at the receiver end of the carbon-wrap barrel.

The .243 Winchester test rifle split the difference between traditional 1:10 rifling twist and the 1:7.5 twist of cartridges such as the 6mm Creedmoor. This was a “Kiwi-made” Hardy Rifle Hybrid distributed by Legacy Sports International, the same outfit supplying Japanese-made Howa rifles. The Hardy Rifle Hybrid includes a switch-barrel/bolt-head design that allows shooting many cartridges from a single rifle. Changing barrels requires less than a minute, a few more minutes required to swap bolt heads. Barrels are cutting-edge, carbon-wrap designs, the ergonomic stock is also 100 percent carbon fiber. The receiver is milled from 7075-grade aluminum. The proprietary spiral-lug head seats into a stainless steel extension of the carbon barrel to make this possible. Everything about the Hardy Rifle is state of the art and precision engineered. It has also proven a highly accurate test vehicle.

Five bullets were chosen for testing, covering the big-game hunter for everything from pronghorn and Coues’ whitetail to bull elk. These included Barnes’ 80-grain TTSX BT, Badland Precision’s 80-grain Bulldozer-2, Barnes’ 85-grain TSX BT, Hammer Bullets’ 88-grain Hammer Hunter and Hornady’s 90-grain CX.  

One stipulation often associated with mono-copper bullets is seating depth. Monolithic bullets can prove frustratingly finicky accuracy-wise. I once believed they just weren’t as inherently accurate as lead-core bullets, until I started seating them a touch deeper than traditional slugs – .010 inch off the lands instead of .005 inch, for instance. This jump into the lands, it is believed by many, helps better “seat” the harder copper into the rifling, providing a better seal and improved accuracy. I have no way of proving this, as it is by no means universal, but it works often enough that I generally follow this rule.               

The Barnes 80-grain TTSX BT (Tipped Triple Shock X, Boat-tail) is a great example of a modern tipped mono-copper design, the blue polymer tip and boat-tail improving aerodynamics while also initiating reliable expansion. It includes a .331 G1 ballistic coefficient (BC). Paired with Alliant Reloder TS 15.5, Hodgdon H-4831sc and Accurate A-4350, this bullet produced a .76-inch group average. The best group resulted from 36.5 grains of Reloder TS 15.5, with three shots going into .43 inch with a muzzle velocity of 3,087 feet per second (fps). The best group from H-4831sc measured .54 inch at 3,140 fps using 45.5 grains of powder; while A-4350 produced a .55-inch group at 3,167 fps using the same measure of powder.

Badlands Precision’s 80-grain Bulldozer-2 is a work of mono-copper art. It includes a sharp aluminum tip, long ogive and sleek boattail that give it an impressive .420 G1 BC (.215 G7) for long-range effectiveness. It is also compatible with standard 1:10-inch rifling twist and the aluminum tip should initiate aggressive expansion on game. The Badlands was paired with Ramshot Hunter, Hodgdon Superformance and Alliant Reloder 15, all groups averaging .77 inch, with two groups skewing that average. Ramshot Hunter produced the best group of the test, that thee-shot, 100-yard group measured .29 inch at 3,143 fps using 44 grains of powder. Superformance also shined, with its best group measuring .35 inch at 3,068 fps using 44 grains of powder. Reloder 15 certainly produced impressive velocities, clocking 3,266 to 3,376 fps, but its best showing was just .80 inch with 40 grains of powder.

The 85-grain Barnes TSX BT (Triple Shock X, Boat-tail) is the Barnes X most of us know best, a hollowpoint monolithic sporting a .333 G1 BC. I’d trust this bullet on larger mountain mule deer or Midwest whitetails, even caribou and black bears. Hodgdon H-4350 and Varget, and Shooters World Match Rifle provided the fuel, and a .77-inch overall group average. H-4350 did best with 41 grains, assembling a .60-inch group at 2,994 fps. Thirty-six grains of Match Rifle managed a .69-inch group at a relatively pokey 2,876 fps. That left Varget, which produced the best group with this bullet, measuring .45 inch at 3,294 fps using 40.5 grains of powder.

After including Hammer Bullets in several tests during the past year, they have impressed with consistent accuracy. They are CNC lathe-turned from pure copper, each bullet weighed and micrometer measured for consistency. The hollowpoint design expands aggressively, shedding petals, while the remaining solid portion pushes deep. The 88-grain Hammer Hunter was chosen here, a long ogive and boat-tail producing a .212 G7 BC. A 1:8-inch twist is recommended for proper stabilization, which excludes its use in many classic .243 Winchester rifles. Shooters World Long Rifle, Alliant Power Pro 200-MR and Vihtavuori N560 were auditioned, resulting in a .65-inch group average. Long Rifle produced excellent results with every load, groups tightening as velocity increased. The “maximum” load of 38.5 grains printed a .44-inch group at 2,980 fps. I put maximum in quotes as I felt that load could be pushed a bit further (as with most published Shooters World data), though I recommend doing so with due caution. Power Pro 2000-MR produced even more impressive results, 38 and 39 grains of powder producing .40- and .50-inch groups at 2,939 and 2,999 fps, respectively. Vihtavuori N540 proved a disappointment in both accuracy and especially velocity with this bullet, so it needs no more discussion.

Hornady said its new CX (Copper alloy eXpanding) bullet represents the most advanced monolithic hunting bullet on the market. Every aspect of the CX has been optimized for long-range performance, greater accuracy, high weight retention and deep penetration. The 90-grain CX includes a .418 G1 BC, and likely requires every bit of the Hardy Rifle’s 1:8 rifling. Powders used for testing included Alliant Reloder 16, Shooters World SW-4350 and Vihtavuori N555. The overall group average was .66 inch, heavily influenced by two 1-inch-plus groups. Reloder 16 produced both impressive groups and top velocities, the best group resulting from a maximum load of 43.5 grains and printing .38 inch at 3,288 fps. SW-4350 turned in the best group with this bullet – .31 inch at 2,852 fps – using 41 grains of powder. N555 turned in one of the worst groups of the test, but redeemed itself with a maximum load of 42 grains, assembling a .42-inch group at a respectable 3,068 fps.

This test certainly proved the accuracy potential of both the Hardy Rifle, and monolithic copper bullets.